Primality Certificate for (11581^2677-1)/11580

Andy Steward10,875 digits16 September 2006
Originally by A.A.D.Steward 2006

This certificate uses a theorem of Brillhart, Lehmer and Selfridge to prove an integer N prime by making use of a partial prime factorization of N-1.

Factorizing N-1

As N is a Generalized Repunit, we make use of the algebraic factorization of N-1 to arrive at the following 34.377275% factorization of N-1:

From Factorisation
1158137 · 313
Φ22 · 5791
Φ33 · 613 · 72937
Φ42 · 17 · 257 · 15349
Φ67 · 19158283
Φ1213 · 13 · 21001 · 5068244569
Φ223457151 · 13799322746827 · c884
Φ44611597 · 1292509 · c892
Φ66912043 · 199455661 · 132223537627 · c1781
Φ892198789337 · 971567741569 · c1785
Φ1338178200193 · c1797
Φ26762677 · 13381 · 751319113 · p3593

From this partial factorization, we use sufficient of the largest prime factors of N-1 so that their product F is at least N 1/3 :

150 1555319859 7453025489 5832362983 9617331176 2921342874 8481360627 3392768844 8940251256 3679816527 6097523320 7068317619 6414520415 5412483222 5440780310 4820721330 7514453595 8127354507 5956671906 3536389165 7991336439 1322950913 2532841219 2541532766 6696375333 6895741535 9921805790 9138081006 2463010618 0462104494 8687677356 8974026447 2259415588 4510413544 6786652568 8519500052 4323472220 2020576226 7468898327 0174794741 8021987661 2781497293 4146806786 1877194657 7227649115 6534382337 3978883167 1386766942 1903037401 0631511500 8828549517 8008883056 9362486625 9873414120 6242680688 4526679989 3746665453 8550222016 4669510871 4073058306 8509886203 1935435224 6754729909 0261999783 0427532160 7054073885 6344453367 7299873322 1780190419 0657663412 1182052851 8342482287 0659037167 0153295014 1498009572 6475821629 1995757522 1679121434 7022385952 0562527745 3599751063 3436073087 3431849939 9602765024 7161638067 8338474303 6290372973 7789788515 7947933904 7885185030 0542750017 8194806785 7223918405 0895589020 5163473772 3499175243 8850948075 2941802944 0764983655 8528962139 5556668898 0144108225 6680057938 7969107541 7113560007 5813935264 1887335807 2050277444 1958935565 9481603598 7875005235 4402210443 7891267692 1559795662 1243905975 4178608526 6173718263 6746640116 3645969662 8564680304 8067700455 3307400931 6725798560 0406835558 6232014705 1458217520 6906727710 3698371258 1899906995 1987522675 4087709538 7765222989 7301287627 0164260584 3651911522 4602985570 1607442216 7914149919 9638180342 7194120406 8691114822 2757510607 1431128846 0897824907 2449325386 3969135375 4777848227 8461116308 7025777318 1956946512 4491952745 3555458401 8390184144 0012068704 4606685527 2188806679 8461176081 2957935149 4782212711 0836175217 8832986676 4684048723 2467183095 3666498492 1565227555 8886911641 4392946164 2409648256 7513725940 1433199171 7620903192 0862898570 0328818653 9529634527 9812560891 4209717103 4234985046 9210370786 7909992712 3575799013 7429581697 1038672827 5532893583 8085148565 9104343796 8806230036 2472077658 8331496366 7457423636 0328879733 1945903191 6654946609 2166923634 4535968328 8992555925 4552819908 0768202577 4244710338 0011389882 8172564862 8943510123 8999246141 6644228737 4084514085 7871496948 8252549602 4662975872 7163122252 4098369134 7671024864 6454424246 4051734084 4067961544 5725247660 0115645897 2909478126 1645620476 2670332416 6907874860 4802131015 4431471603 8673855543 2219771487 4821098947 0620080918 7382507146 3063492020 0060954088 2897119352 1771504094 7014079306 8077589652 1730579131 4688636868 8619319528 8964328383 7849073967 6997021847 1958155539 8317209428 8143462830 8739731279 6346996141 9097355557 6016106240 4695247859 4717284560 8955984348 4358495906 5549522813 6349290097 1967303364 9486456442 3142185950 9661820332 8499737360 9398110169 9295672273 7173051201 0328648235 3442822273 3884040552 7486861068 8041470820 3041651266 5118740391 8529654466 4684505429 1700049824 0759420475 9452889434 6584419359 2800284848 6611165332 1164851961 3303967056 3012757816 9578345769 3024205016 9226097342 4697390539 3734167108 2429959324 7092641963 5106535713 0733662935 6349285383 6399222519 9543535167 9464930084 6155621732 1410863585 3034639804 4984710028 3517004802 9099076576 8553480527 7766184850 2026239065 2122424377 2332205613 1378011217 3065405775 3740007729 1883036497 6734737405 3837476700 8727694418 8111073610 9038892666 1838266831 3733774366 0228197916 6307917087 4695491078 5386038025 6819583967 0468536396 4382304870 2712171097 0752692164 2389373582 0366648818 7510786710 3900722576 6254096073 8322390728 1828188500 2263103810 3143409847 7454560983 7598277768 2257938554 6008729051 9767222104 0636359470 3759795080 0312781525 4579668005 4526102979 9077397808 2225902014 2547273702 6860108379 7777215767 6931871686 5411008101 7735713525 4231684188 2952108901 3631397371 3923089453 9346698478 9618317221 3965647689 7289220549 6292541660 6029413987 1926664240 6477460641
1379 9322746827
97 1567741569
13 2223537627

Note that all prime factors listed above have been proven. As primes of under 250 decimal digits can be verified in a few seconds, proof of their primality is not included here, in order to save space. Larger prime factors can take from hours to months to prove; certificates for all such factors have been PKZIPped into this file.

We set R = (N-1)/F. Note that GCD(F,R)=1 and Log(F)/Log(N) = 33.366104%

Finding a Witness to Primality

Next, we find an integer witness w such that for each prime factor p of N-1, w(N-1) ≡ 1 mod N and GCD(w(N-1)/p-1,N) = 1. In this case, w = 2 suffices.

Express N in base F

As F2 < N < F3 and N ≡ 1 (mod F), we can let N = c2·F2 + c1·F + 1.

Brillhart, Lehmer and Selfridge's Theorem shows that N is prime if and only if c12-4·c2 is not a square.

Here, c12-4·c2 is ≡ 48 (mod 63) and therefore cannot be a square and N is prime.