Unique prime


In recreational number theory, a unique prime or unique period prime is a certain kind of prime number. A prime p2, 5 is called unique if there is no other prime q such that the period length of the decimal expansion of its reciprocal, 1 / p, is equal to the period length of the reciprocal of q, 1 / q. For example, 3 is the only prime with period 1, 11 is the only prime with period 2, 37 is the only prime with period 3, 101 is the only prime with period 4, so they are unique primes. In contrast, 41 and 271 both have period 5; 7 and 13 both have period 6; 239 and 4649 both have period 7; 73 and 137 both have period 8; 21649 and 513239 both have period 11; 53, 79 and 265371653 all have period 13; 31 and 2906161 both have period 15; 17 and 5882353 both have period 16; 2071723 and 5363222357 both have period 17; 19 and 52579 both have period 18; 3541 and 27961 both have period 20. Therefore, none of these is a unique prime. Unique primes were first described by Samuel Yates in 1980.
The above definition is related to the decimal representation of integers. Unique primes may be defined and have been studied in any numeral base.

Period of a prime in base ''b''

The representation of the reciprocal of a prime number in the numeral base is periodic of period if
where is a positive integer smaller than According to the summation formula of geometric series, this may be rewritten as
In other words, is a period of the representation of if and only if is a divisor of
Euler's theorem asserts that, if an integer is coprime with, then is a divisor of where is Euler's totient function. This proves that, for every integer coprime with, the representation of the reciprocal of is periodic in base.
All the periods of a periodic function are multiples of a shortest period generally called the fundamental period. In this article, we call period of in base the shortest period of the representation of in base. Therefore, the period of in base is the smallest positive integer such that that is a divisor of
In other words, the period of a prime in base is the multiplicative order of modulo.
According to Zsigmondy's theorem, every positive integer is a period of some prime in base except in the following cases:
As
where is the th cyclotomic polynomial, the primes of period in base are prime divisors of More precisely, the primes of period are exactly the prime divisors of that do not divide .
If is even, the prime divisors of that do not divide are exactly the prime divisors of
This is wrong if is odd: if and , where is a positive integer, then
although 2 divides both and
If is odd, the primes of period are exactly, if, the prime divisors of, or, if, the odd prime divisors of.
As the period of every prime divides , if divides, then its period is smaller than. Conversely, if divides and has a period smaller than, then it is a common divisor of and As the resultant of two polynomials is a linear combination of these polynomials, divides the resultant of and As these two polynomials are coprime and divide divides also the discriminant of Thus, a prime divisor of, that has a period smaller than, is also a divisor of.
Now, we have to prove that, if a prime divides and then it does not divide In fact, this implies immediately that does not divide If is even, 2 cannot divide , and the condition is not restrictive.
Thus, let. It suffices to prove that does not divides for some polynomial, which is a multiple of We take
By Fermat's little theorem, we have As divides, we have also Thus the multiplicative order of modulo divides, which is a divisor of. Thus is a multiple of. Now,
As is prime and greater than 2, all the terms but the first one are multiple of This proves that does not divides
A prime is a unique prime in base, if and only if, for some, it is the unique prime divisor of that does not divide. If is even this means that
for some positive integer .
If is odd, this means that
for some integers and. This provides an efficient method for computing the unique primes and the primes of a given period.
Note that a prime divisor of is coprime with, and thus also with its divisor Such a prime has no period length, as the representation in base of its reciprocal is finite instead of being periodic. Thus, such a prime is never considered as a unique prime, even if it is the unique prime that has a finite reciprocal in base. For example, 2 is not considered as a unique prime in binary, although it is the only prime with finite reciprocal in binary.
The mention "terminated" means that the prime divides the base, and thus that the representation of its reciprocal is finite.

23456789101112131415161718192021222324
211111111111
3212121212121212
54421442144214421442
736362136362136362136
11105551010105211055510101052110
13123641212436122112364121243612
178164161616881616164168218164161616
19181899936918361818189921181899
23111111221122111122221111222211221122222221
29282814141472814282841428287428287281477
315305361551515303030151053015151530301030
37361818364912936936123693636363618361236
412081020404020454040408405405402020401040
431442742361421217422121217214242427142121
472323234623232323464623462346232323464623464623
53525226522626522613265213521313265252525252413
595829292958295829585829585829292958292929295858
6160103030606020560415361515606030512152020
676622332233662211336666661111333366336633113311
7135353553570353535703570103535103535770701435
73912972362436872367272729241836722483612
7939783939787813391339263926263926133939131336
838241418282418241414141828282414182828241824182
89118811448888114444228888888114444884444228888
97484824961296162496481696969612961632329649624
10110010050251010010050410010050101002510100255050505025
1035134511021025117173410210217175151515151102102341734
1071065353106106106106535353535353106531061065310610610653106
1093627182710827122710810854108108279361083654272736108
113281121411211214285611256112562847112811211211256112112
127712674212612676342631266312663763633663912618
131130656565130651306513065656513065651302626656513013026
137681363413613668686886813613634341768346813613634136136
1391381386969236946694669138694613869138138138691381384669


Bold for unique primes.

23456789101112131415161718192021222324
123252, 37232, 5112, 3132, 73, 52172, 3192, 53, 72, 1123
23537351131373, 51731953, 7112335
37137314319737, 13377, 19157612112417, 133077127421463137, 79601
45517133755, 1341101615, 295, 171971132575, 295, 1318140113, 175, 975, 53577
5311111, 3111, 71311280131, 15111, 6141, 2713221226213094111, 376111, 493111, 31, 418874141, 2711151, 91111, 61, 25140841245411292561346201
67137314319737, 13377, 19157612112417, 133077127421463137, 79
7127109343, 127195315598729, 4733127, 337547, 1093239, 464943, 45319659, 494352290438108731174346329, 43, 113, 12725646167449, 80207701, 7084129, 71, 3271943, 631, 33191696842129, 533671729, 239, 28771
817412573131297120117, 24117, 19373, 137732189, 2331428141, 93717, 14896553741761113, 92917, 38331600019724173, 3209139921331777
97375719, 7319, 82919, 246737, 106326265719, 37, 757333667177289337, 807491609669397, 18973541, 2106119, 37, 73, 10919, 1270657991, 34327523, 299896400800185775383127, 29761319, 779200319, 2017, 4987
1011614152111, 10111, 19111, 33111819091134211914111, 241171, 10131, 15316168111, 71, 10111, 904111, 225115238118564122407131, 41, 21111, 5791
1123, 8923, 385123, 89, 6831220703123, 31547571123, 29345923, 89, 59947923, 67, 661, 385121649, 51323915797, 180611323, 26698108923, 419, 859, 1804167, 4027, 115453967, 463, 2333, 853723, 89, 397, 683, 2113214199351922723, 199, 16127, 51217104281, 62060021107789473684211751387502711167, 353, 1176469537393723040460367, 7349, 134367047
12137324160113, 9713, 18137, 1096481990113, 1117205932839337, 103313, 387797, 67383233229, 45713, 76913, 1227761, 3181157, 148937, 754913, 73, 349
1381917971612731, 81913051757813433, 7608911614816840179, 8191, 121369398581, 79716153, 79, 2653716531093, 3158528101477517, 2036923353, 264031, 1803647157, 2991424917153, 157483, 1665515953, 157, 1613, 2731, 8191212057, 291919685379, 521, 29759719289599, 29251, 1333388693121, 142559, 969053979, 189437, 51609415179, 2003, 8510743766347691619, 48039349953, 6553, 15913, 6895253
144354729, 11329, 44929, 197113, 91143, 541929, 164939090911623931211, 1306329, 22079702756710678711157903212279659332222107197, 226871827, 105298186766129, 43, 8696971, 673, 2969183458857
151514561151, 331181, 17411171, 120131, 159871631, 2331131, 271, 456131, 290616119501944161, 661, 97814651, 16197131, 2851, 1551161, 3922530161, 151, 331, 1321656676000131, 601, 55872131, 211, 246018131, 3001, 261451211, 9391, 1818161, 85879419174912328481241, 17881, 24481
1625717, 1936553717, 1148917, 9880117, 16955397, 257, 6732152336117, 588235317, 630467317, 97, 26075340786536117, 5393, 160977121, 179953641, 670041718913, 18441797, 11360784115073, 56337717, 150588235362897, 30067317, 322799256117, 3697, 62300917, 2801, 2311681
171310711871, 3451143691, 131071409, 466344409239, 409, 1123, 3083914009, 2767631689103, 2143, 11119, 131071103, 307, 1021, 1871, 345112071723, 5363222357505447028499293772693651, 74876782031103, 443, 15798461357509103, 227717301936752771045002649, 6734509609137, 953, 26317, 43691, 13107110949, 1749233, 269953873375637078191650399033044803, 999952826319476898526315789473684211502097124754084594737239, 74729519, 176634767651103, 62246266355102810647307, 120574031, 341563234253
181919, 3737, 1095167464411173078721153071319, 525795900771657, 180119, 271, 93719, 13204919, 739, 811433, 387371423, 565373, 465841199, 236377307, 6948119, 37, 199, 61319, 5966803163, 271, 1117127, 199, 7561
195242871597, 363889174763, 524287191, 6271, 3981071191, 638073026189419, 453416674040332377, 524287, 12128471597, 2851, 101917, 363889111111111111111111161159090448414546292904363630642026607712865927, 94689400044494597156891499164920914272113, 370649274902657229, 457, 174763, 524287, 525313229, 1103, 202607147, 2919737236841, 608988490980281242310991220309223964384022175368484119, 19269610456112061389013, 5492110662400345943, 341203, 974045960024232129, 63877469, 249392186136137282588256957615350925401
204111816168141, 9161241, 6781281, 402141, 61, 1321425217613541, 2796121260184185403261421, 601, 6411061, 138388119421, 131381427825536121881, 6354115101, 1455011693664712141, 2801, 22236141, 920421641181, 401, 15090161, 941, 27234161, 1801385941
21337368089337, 5419379, 51949918224289311189866484992737, 64965743, 2269, 36808943, 1933, 108386891723, 8527, 27763817782484318943, 337, 547, 271437743, 547, 223900089143, 2817034275427337, 1429, 5419, 1444943, 13567, 94014370915610719208425730640261, 68443621460951, 84427335314789, 6427, 2276334071227183683613841943, 170689, 40803042143, 10426753, 78066619
2268367, 661397, 211323, 67, 52815182815123, 1074634167, 683, 208575501, 57046123, 4093, 877923, 89, 199, 583675715449005312801145671723, 1173787005723, 23504771357353, 293154241723, 947, 87415373536801, 630130723, 25323969325723, 42401656314723, 6073, 1036252989, 2854510510073970040657974760867245726761
2347, 17848147, 100152317947, 178481, 27962038971, 33220736136147, 139, 3221, 750594489147, 3083, 3147982339675747, 178481, 1005267893803947, 1001523179, 2353579470711111111111111111111111829, 28878847, 374022198123147, 39891250417, 3212184382431381, 251954534234933118314347, 461, 2347, 10627, 2249861, 14525237829, 31741, 304646215183156576947, 277, 1013, 1657, 30269, 178481, 279620347, 2655261821922809016297748147, 599, 7468009, 20801237997245359277, 2347, 16497763013, 1335495402823691, 1381, 4626627909792148307865147, 19597, 1398705661151032828477374463, 1323064018651, 60575166785239461, 1289, 831603031789, 192064739191347, 124799, 304751, 58769065453824529
24241648197, 673390001167832173, 193, 409433, 3873797, 577, 7699999000110657, 20113193, 222777781570216114757506412562840001193, 2225337773, 1321, 72337110198556014297, 395239331177, 82111373, 518118697191353, 286777937, 8357599397, 1134793633

Decimal unique primes

At present, more than fifty unique primes or probable primes are known. However, there are only twenty-three unique primes below 10100. The following table lists all 23 unique primes below 10100 and and their periods and
Prime
13
211
337
4101
109,091
129,901
9333,667
14909,091
2499,990,001
36999,999,000,001
489,999,999,900,000,001
38909,090,909,090,909,091
191,111,111,111,111,111,111
2311,111,111,111,111,111,111,111
39900,900,900,900,990,990,990,991
62909,090,909,090,909,090,909,090,909,091
120100,009,999,999,899,989,999,000,000,010,001
15010,000,099,999,999,989,999,899,999,000,000,000,100,001
1069,090,909,090,909,090,909,090,909,090,909,090,909,090,909,090,909,091
93900,900,900,900,900,900,900,900,900,900,990,990,990,990,990,990,990,990,990,991
134909,090,909,090,909,090,909,090,909,090,909,090,909,090,909,090,909,090,909,090,909,091
294142,857,157,142,857,142,856,999,999,985,714,285,714,285,857,142,857,142,855,714,285,571,428,571,428,572,857,143
196999,999,999,999,990,000,000,000,000,099,999,999,999,999,000,000,000,000,009,999,999,999,999,900,000,000,000,001

The prime with period length 294 is similar to the reciprocal of 7
Just after the table, the twenty-fourth unique prime has 128 digits and period length 320. It can be written as 2 + 1, where a subscript number n indicates n consecutive copies of the digit or group of digits before the subscript.
Though they are rare, based on the occurrence of repunit primes and probable primes, it is conjectured strongly that there are infinitely many unique primes.
the repunit /9 is the largest known probable unique prime.
In 1996 the largest proven unique prime was /10001 or, using the notation above, 141 + 1. It has 1128 digits. The record has been improved many times since then. the largest proven unique prime is, it has 20160 digits.

Binary unique primes

The first unique primes in binary are:
The period length of them are:
They include Fermat primes, Mersenne primes and Wagstaff primes.
Additionally, if n is a natural number which is not equal to 1 or 6, than at least one prime have period n in base 2, because of the Zsigmondy theorem. Besides, if n is congruent to 4 and n > 20, then at least two primes have period n in base 2, because of the Aurifeuillean factorization, for example, 113 and 29 both have period 28 in base 2, 37 and 109 both have period 36 in base 2, and that 397 and 2113 both have period 44 in base 2,
As shown above, a prime p is a unique prime of period n in base 2 if and only if there exists a natural number c such that
The only known values of n such that is composite but is prime are 18, 20, 21, 54, 147, 342, 602, and 889. It is a conjecture that there is no other n with this property. All other known base 2 unique primes are of the form.
In fact, no prime with c > 1 have been discovered, and all known unique primes p have c = 1. It is conjectured that all unique primes have c = 1.
As of September 2019, the largest known base 2 unique prime is 282589933-1, it is also the largest known prime. With an exception of Mersenne primes, the largest known probable base 2 unique prime is, and the largest proven base 2 unique prime is. Besides, the largest known probable base 2 unique prime which is not Mersenne prime or Wagstaff prime is.
Similar to base 10, though they are rare, it is conjectured that there are infinitely many base 2 unique primes, because all Mersenne primes are unique in base 2, and it is conjectured they there are infinitely many Mersenne primes.
They divide none of overpseudoprimes to base 2, but every other odd prime number divide one overpseudoprime to base 2, because if and only if a composite number can be written as, it is an overpseudoprime to base 2.
There are 52 unique primes in base 2 below 264, they are:
Prime Prime
2311
45101
37111
10111011
12131101
8171 0001
18191 0011
5311 1111
204110 1001
144310 1011
973100 1001
7127111 1111
151511001 0111
242411111 0001
162571 0000 0001
303311 0100 1011
213371 0101 0001
2268310 1010 1011
262,7311010 1010 1011
425,4191 0101 0010 1011
138,1911 1111 1111 1111
3443,6911010 1010 1010 1011
4061,6811111 0000 1111 0001
3265,5371 0000 0000 0000 0001
5487,2111 0101 0100 1010 1011
17131,0711 1111 1111 1111 1111
38174,76310 1010 1010 1010 1011
27262,657100 0000 0010 0000 0001
19524,287111 1111 1111 1111 1111
33599,4791001 0010 0101 1011 0111
462,796,20310 1010 1010 1010 1010 1011
5615,790,3211111 0000 1111 0000 1111 0001
9018,837,0011 0001 1111 0110 1110 0000 1001
7822,366,8911 0101 0101 0100 1010 1010 1011
62715,827,88310 1010 1010 1010 1010 1010 1010 1011
312,147,483,647111 1111 1111 1111 1111 1111 1111 1111
804,278,255,3611111 1111 0000 0000 1111 1111 0000 0001
1204,562,284,5611 0000 1111 1110 1110 1111 0000 0001 0001
12677,158,673,9291 0001 1111 0111 0000 0011 1110 1110 0000 1001
1501,133,836,730,4011 0000 0111 1111 1101 1110 1111 1000 0000 0010 0001
862,932,031,007,40310 1010 1010 1010 1010 1010 1010 1010 1010 1010 1011
984,363,953,127,29711 1111 1000 0000 1111 1110 0000 0011 1111 1000 0001
494,432,676,798,593100 0000 1000 0001 0000 0010 0000 0100 0000 1000 0001
6910,052,678,938,0391001 0010 0100 1001 0010 0101 1011 0110 1101 1011 0111
65145,295,143,558,1111000 0100 0010 0101 0010 1001 0110 1011 0101 1011 1101 1111
17496,076,791,871,613,6111 0101 0101 0101 0101 0101 0101 0100 1010 1010 1010 1010 1010 1010 1011
77581,283,643,249,112,9591000 0001 0001 0010 0010 0110 0100 1100 1101 1001 1011 1011 0111 0111 1111
93658,812,288,653,553,0791001 0010 0100 1001 0010 0100 1001 0011 0110 1101 1011 0110 1101 1011 0111
122768,614,336,404,564,6511010 1010 1010 1010 1010 1010 1010 1010 1010 1010 1010 1010 1010 1010 1011
612,305,843,009,213,693,9511 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111
859,520,972,806,333,758,4311000 0100 0010 0001 0100 1010 0101 0010 1011 0101 1010 1101 0111 1011 1101 1111
19218,446,744,069,414,584,3211111 1111 1111 1111 1111 1111 1111 1111 0000 0000 0000 0000 0000 0000 0000 0001

After the table, the next 10 binary unique prime have period length 170, 234, 158, 165, 147, 129, 184, 89, 208, and 312. Besides, the bits of them are 65, 73, 78, 81, 82, 84, 88, 89, 96, and 97.

Bi-unique primes

Bi-unique primes are a pairs of primes having a period length shared by no other primes. For example, in binary, the bi-unique primes with at least one prime less than 10000 are:
prime
p
the only other prime having the same period as pperiod
length
238911
2911328
3710936
4717848123
59303316958
61132160
672085766
7112292135
7912136939
83883141869782
892311
9767348
10728059810762433106
1093736
1132928
139168749965921138
1675791261411327564908772183
1932225337796
22361631817737
251405150
26310350794431055162386718619237468234569131
2818617170
28316576853752194
353293154241788
397211344
4333873772
4634982397651178256151338302204762057231
571160465489114
577487824887233144
601180125
6071512768222413735255864403005264105839324374778520631853993303
6312331145
641670041764
64384115747449047881488635567801214
6739748
7271786393878363164227858270210279121
7512139731020464054092520609592459940706818275139793055476751375
769442499826945303593556473164314770689384
91975582488424179347083438319153
103919709014643115560219397264671577125505264032974428376489237001990435774189483906244488746953221813209519
1291838618178719251837397922064707038627665630534568678134599691846785465476947935734685898757453150811290
13216160
13272365454398418399772605086209214363458552839866247069233221
14291444984
1471252359902034571016856214298851708529738525821631245
15434965395030068548134274243124972075225434447114375481299036593442726326832727934403424309955102162841656341524725641213163998408700663382552888660520657771
169799335205800663868215396640964567095667094665346141013294320587365443384719802857319737050495099341955640963272958071602273848
17531795918038741070627146
17772578108374
180160125
211339744
22813011347479614249131190
280111145132193671570675428136093613069572578905311347753278750670385944813932208040513667887871284097315136663768514951512818176703814685283876011400
297148912491110
30116312150089477061873428304941256607333600920196596819228838233920151217543848707440440743378874829368708525195829606739455618101487108509344497125490909345722920980889720610296509391055922632562936762745985295939373868333158897482139484909581327574321667019011971699720667276359293324375439719347759613010
32599608438509865329765324662357734834928406188192322061450101434800447027087799672414395190371588009172302891086
336188959882481168
396732968108233318274440144048319435585886318034350504042370424857657144863375058430117414872255393214792759763174234741148533763213807829065021067587667839348669521241172404848393326689145668069886029314021174165239553294235608563348263331769545752945501042634044143687612620795868425425868697802548422772617813286576369930648977321277113638704269538525368282422919912496852067831211903498208045531983
405125150
412933770734168253651800370989375796994825389296318018601048482005531172856260013942500368975908606689688
4177985773715546387
4523106788290443848295284382097033266
4561510499030505981560130624776542416406578290250029762044510602610086894781587157297451609248604675303096573768271042333081577723501646221586511876941091127277966639771579212280
487182033219963138371097689272308258116841679442057301643873942124991182012434598644913857356023840478815121709542915222280972560231358838127531337487
515354410972897112
52818605734143690089694576381015338273647046841642861888243839968714716267644682194294328506497982344887910369772959521853052813685869223602401618305704978858302418131626414479003507027951243212640
5347242099935645987198
543194967929889733952798348096615692513205440143056295353390411760039938046764851994701460617667146742458574846920351467698967352630946097466436554549903077403247938707892111836393026576020062067279983571553515883749049268826780746332528777724421349387127192164228259193054156469698384449562295598055020599062286915512841529080499645635164055241270282948847165082731875146179051130126423169926185686296640469155148715758750884577847212715
5881236182562448406188572125221558517145982594227534969066416811777487104605150384033661984737737704411470
60434475130366518102084427698737318
6659673480918906267571379147730480801519827880098089533495229717036762090724479192537367139437198393219309210019204431468329644945358062861533367588087648270529222845279877353690826582261557527588377345857885839204370316799678327986978745315063758482953060020699742926470125329753826578693958965495360840266430868491687076380359846529517564492323819228415082790434495536836421658955188522736168537521926265470822252323226622033496174216244501061303611330330509969775174567807593369800175040355534432048366366635839506581617182643750350340079505634187776845404465707422776826888198169305292494021412276744678617840421846647032730657721456263070083330217279102956893078978125921763407971896625474982986290414196871234129842105803253764818463163965664137011098487553488787905622962752952661907888801221518355677716658155656118632614701678572886850142421155051821596857535766122394772866202385830712929707343895805217305407898539596073224024658456277734094594213402504761256658599260031211384124977353605696658
67192150061062571132232545030150231494321261931502937914161854451735782815972183153772965895845912286020411839075325848150684717472911773868989256224772085301157149623552948421351378904743949493392492593354077100185844800551578253870894169122332527140542470182165979947950591615679223024502772813511358383931714240388326884322400783612641615239043555390859277387539681570185502584761638520908267561579157052834132260008161517125438385810662816006502786905347193711129973931907210681368405967905259504808513705102775602483411823418055530540005873783847859946958755873949052267031496056898302577682299877147709491924833025835697991410798675970511901340787180117305084825425672844188381190005634439855936912212030601370476487130955028777752900629072085087272690171309166916768388174525299649388783493957856424305718522418374616041363744484437301750818895020562905124977171775774927365557840817319985657655985181048225165203403017010341239267674727846657767794806288216282796876517361985413308022384051547862480430733359
748726828803997912886929710867041891989490486893845712448833197
8929197107422273014301919781414466039325387889623676342705850752210599969496
8969105085375848729800497877494145054402385436616845064164452498921883291912678976696572426254056550259022949969657136812477008949535672765969651143081836499574699312620294703721884924945056142078277741715754321142971230033732570350705429405324111863224178094111236842467383427204559334241753996710442865576380755911121
954716214412921607393124844026434888102109534609167583340475939523423109823488991255233752076373043337782118690623929880990598025280195936822349417554227588856563950687223850379806574662576181125821887709213121001255113378364125317181543958215292109223894437336163542688202195778635777594590824472189272736956682232512589430067436149096397611271617048168626262363530326221157951922451250830912610290539880533164333771738950187937400525482660150187567631507317253854563322329824335760155477225639780725543780000157070718213714508429106480529302767645353034241674787475797715924842708009785619594111833671334989692364348461088652067648899779635540702959360927954846633269257242776203860773815514730097331789909830134870856761851443784849028849559721048736065581730862674995475660817808180648576715674801960016932368351368110361107685467939296107329092742272964070795457885208118374951815864201178076670335933944739546

Although there are 1228 odd primes below 10000, only 21 of them are unique and 76 of them are bi-unique in binary.
A classic example of binary bi-unique primes are
and
they are the two prime factors of the Mersenne number 21061−1. Thus, the period
length of them is 1061.
As of October 2016, the largest known probable binary bi-unique prime is, it has a period
length of 5240707 shares with only the prime 75392810903.
Similarly, we can define "tri-unique primes" as a triple of primes having a period
length shared by no other primes. The first few tri-unique primes are:
prime pthe only two other primes having the same period as pperiod
length
53157, 161352
1018101, 268501100
1032143, 1111951
131409891, 7623851130
137953, 2631768
15753, 161352
163135433, 272010961162
17962020897, 18584774046020617178
18154001, 29247661180
191420778751, 3032715267195
19719707683773, 4981857697937196
199153649, 3305780695999
211664441, 1564921210
229457, 52531376
2331103, 208929
271348031, 49971617830801135
3072857, 6529102
317381364611866507317969, 604462909806215075725313316
3591433, 1489459109360039866456940197095433721664951999121179
36755633, 37201708625305146303973352041183
373951088215727633, 4611545283086450689372
4193410623284654639440707, 1607792018780394024095514317003418
421146919792181, 1041815865690181420
4319719, 209986343
4392298041, 936197313260973
4434714692062809, 4507513575406446515845401458366741487526913442
457229, 52531376
46727961, 352369374013660139472574531568890678155040563007620742839120913466
49115162868758218274451, 50647282035796125885000330641490

In binary, the smallest n-unique prime are
In binary, the period length of odd primes are:
primeperiod
length
primeperiod
length
primeperiod
length
primeperiod
length
primeperiod
length
primeperiod
length
primeperiod
length
32793918118029329242142055755667348
5483821919530710243143563562677676
738911193963111554337256928468322
1110974819719631315643973571114691230
131210110019999317316443442577144701700
1781035121121033130449224587586709708
1918107106223373372145776593148719359
231110936227226347346461460599299727121
2928113282297634934846323160125733244
31512772332935388467466607303739246
3736131130239119359179479239613612743371
41201376824124367183487243617154751375
431413913825150373372491490619618757756
47231491482571637937849916663145761380
53521511526313138319150325164164769384
595815752269268389388509508643214773772
616016316227113539744521260647323787786
67661678327792401200523522653652797796
713517317228170409204541540659658809404
73917917828394419418547546661660811270

In binary, the primes with given period length are:
period
length
primeperiod
length
primeperiod
length
primeperiod
length
prime
126273151103, 2143, 1111976229, 457, 525313
23272626575253, 157, 161377581283643249112959
372829, 113536361, 69431, 203944017822366891
4529233, 1103, 20895487211792687, 202029703, 1113491139767
5313033155881, 3191, 201961804278255361
63121474836475615790321812593, 71119, 97685839
712732655375732377, 12128478283, 8831418697
817335994795859, 303316983167, 57912614113275649087721
973344369159179951, 3203431780337841429, 14449
10113571, 1229216061, 1321859520972806333758431
1123, 893637, 109612305843009213693951862932031007403
121337223, 61631817762715827883874177, 9857737155463
138191381747636392737, 64965788353, 2931542417
14433979, 12136964641, 670041789618970019642690137449562111
151514061681651452951435581119018837001
162574113367, 1645113536667, 2085791911, 112901153, 23140471537
1713107142541967193707721, 76183825728792277, 1013, 1657, 30269
181943431, 9719, 209986368137, 953, 2631793658812288653553079
1952428744397, 2113691005267893803994283, 165768537521
204145631, 2331170281, 8617195191, 420778751, 30327152671
2133746279620371228479, 48544121, 21288583396193, 22253377
22683472351, 4513, 1326452972433, 387379711447, 13842607235828485645766393
2347, 1784814897, 67373439, 2298041, 9361973132609984363953127297
24241494432676798593741777, 2578108399199, 153649, 33057806959
25601, 180150251, 405175100801, 10567201100101, 8101, 268501

Period lengths

Period
length
PrimesPeriod
length
PrimesPeriod
length
PrimesPeriod
length
PrimesPeriod
length
Primes
132143, 1933, 108386894183, 1231, 538987, 20176370990032280374865794236161733, 4637, 329401, 974293, 1360682471, 106007173861643, 706170999015615947981163, 9397, 2462401, 676421558270641, 130654897808007778425046117
2112223, 4093, 877942127, 2689, 45969162909090909090909090909090909091822670502781396266997, 3404193829806058997303
337231111111111111111111111143173, 1527791, 1963506722254397, 21409920153955266416310837, 23311, 45613, 45121231, 1921436048294281833367147378267, 9512538508624154373682136329, 346895716385857804544741137394505425384477
410124999900014489, 1052788969, 10566892616419841, 976193, 6187457, 83442740657856184226549, 4458192223320340849
541, 2712521401, 25601, 18252121300145238681, 418550283013311072165162503518711, 553839699736402405628651064078060048185262533041, 8119594779271, 4222100119405530170179331190291488789678081
67, 1326859, 10583130494647, 139, 2531, 54979718449191766599144041, 1834118381718657009401, 2182600451, 7306116556571817748755241
7239, 464927757, 4403346547776314735121409, 31636290876345852500140615403872638227967493121, 79863595778924342083, 28213380943176667001263153660999177245677874003, 72559, 310170251658029759045157793237339498342763245483
873, 1372829, 281, 1214994494899999999000000016828559389, 1491383821, 232455746567182988617, 16205834846012967584927082656402106953
9333667293191, 16763, 43037, 62003, 7784383939749505885997, 197673014459819096356802301467933369277, 203864078068831, 159535208632922464434897889389497867, 103733951, 104984505733, 5078554966026315671444089, 403513310222809053284932818475878953159
10909130211, 241, 216150251, 5051, 78875943472201704147571, 2652127932496176419029611, 3762091, 8985695684401
1121649, 513239312791, 6943319, 5733641506379060435951613, 210631, 52986961, 1316816456142987771241573142393627673576957439049, 4599481134788684631022172889522303430183991547, 14197, 17837, 4262077, 43442141653, 316877365766624209, 110742186470530054291318013
12990132353, 449, 641, 1409, 6985752521, 1900381976777332243781723169, 98641, 3199044596370769921289, 18371524594609, 4181003300071669867932658901
1353, 79, 2653716533367, 134462821031329837353107, 1659431, 1325815267337711173, 471988587994914256602000717312171337159, 1855193842151350117, 4920734163464632693400173948250213148744663793900900900900900900900900900900990990990990990990990990990991
1490909134103, 4013, 219938333695470541929, 14175966169747253, 422650073734453, 296557347313446299946299, 4855067598095567, 297262705009139006771611927
1531, 29061613571, 123551, 102598800232111471551321, 62921, 83251631, 130063569267805835883012175151, 4201, 1576398555373919170916417094006315195191, 59281, 63841, 1289981231950849543985493631, 965194617121640791456070347951751
1617, 588235336999999000001567841, 12752200102015050376176722817036322379041, 13697781874905924619697, 206209, 66554101249, 75118313082913
172071723, 5363222357372028119, 247629013, 22123942967702033680135721319, 10749631, 3931123022305129377976519775237, 42043, 29920507, 1366146685760023293714964475559157409101810439712004721, 92556179448994367391887834053878562534782033760810527051075248738484727059555245899601591
1819, 52579389090909090909090915859, 15408320493066255778120184978157, 6397, 216451, 38884780849398197, 5076141624365532994918781726395939035533
19111111111111111111139900900900900990990990991592559647034361, 434087628565746021214453428992855982675574675179317, 6163, 10271, 307627, 49172195536083790769, 366057476272552146152714056487508046107991799199, 397, 34849, 362853724342990469324766235474268869786311886053883
203541, 27961401676321, 59648480816061, 4188901, 39526741805070721, 1972106116664671749835968110060101, 7019801, 14103673319201, 1680588011350901

Unique prime in various bases