Primality Certificate for (10247^2081-1)/10246

Andy Steward8,343 digits19 September 2005
Originally by A.A.D.Steward 2005

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 42.441240% factorization of N-1:

From Factorisation
1024710247
Φ22 · 2 · 2 · 3 · 7 · 61
Φ42 · 5 · 17 · 73 · 8461
Φ51811 · 154691 · 39359161
Φ82 · 41 · 89 · 13121 · 115137329
Φ1011 · 1002194186424511
Φ1321700901 · 5120908428637 · 12060864644511216443800719713
Φ162 · 23857 · 59417537 · 42875916664759946609
Φ205 · 401 · 60626082835006547442851826781
Φ261249 · 322374131 · p37
Φ322 · 353 · 2593 · 306283700702315737722689 · p35
Φ40241 · 1801 · 8557461761 · 7315033528660979081 · p30
Φ5253 · 253501 · c90
Φ651124238002788368131 · c175
Φ806911761 · 58639531201 · c111
Φ104313 · 14354393 · c183
Φ130131 · 1171 · c188
Φ160c257
Φ2083121 · 17024068049 · c372
Φ2602861 · 107627018514601 · c368
Φ416506689 · c765
Φ520521 · 485161 · c762
Φ104028081 · c1536
Φ20802081 · 14561 · 39521 · 403574081 · 31696143263201 · p3046

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 :

897578 6459891235 4771641731 1454294695 0314254963 7434195799 7332800491 6819238383 5284358283 8794974038 3666984472 2431177435 3722791960 2095053345 0631166023 1855145905 2587528349 1271822677 3172520267 6148665960 5301644819 3477839870 3200422581 5771174620 8732620574 7503897412 4533798639 9190898242 4367803570 5390125778 4086104897 1983563679 4250182377 9395508592 6714115112 9299849855 1474973327 6467783041 9062042128 7802210645 2217493513 3416287937 0198012007 9472901103 7598517044 1933080767 5074941840 9468146138 2250630805 3924343167 3817642058 5011806327 6045177389 5598128517 9830713045 8097223938 6929953589 6890714553 6739897623 5759965998 3982282767 4472120722 3192292103 4674226263 6179682667 7931612442 6066518764 6165475103 7766566140 9927468726 4552437843 8557329944 3107554488 0973856879 8858886930 9786371579 2870027822 8905236542 5852243398 7103579225 9709156348 2217743762 6289385416 7344830483 8015543142 2543937437 5510994765 6718845480 9372899419 9621868422 3097855077 9905977807 6131181359 0866929506 7092673580 7462845474 0223938202 8846516304 7350809106 5770903537 0957086611 1616611421 0610393297 2743538358 4376453635 8112028827 2589226054 3740738481 9337990536 8435356688 5876785974 4046907801 5709967175 3859747094 3095460758 8915627537 9304821023 6520666887 0735406834 1279136270 8820891400 1363146298 4581642218 8500829978 9697537514 9882469440 2522498749 7269613068 9980344678 4954831477 3916369789 9357324684 6066949527 5390111409 1718202966 9044249966 8289188768 7486232254 4984175598 5366745753 5786481101 6685153041 0192115057 8523483278 2048715572 9927185731 7007317756 8715391630 6310132526 7976249021 9434497040 8576282152 0564570699 0325246902 8482015387 6889130827 2213846469 9502633745 4478121864 9710769098 1272076251 6081348261 4632220061 6091172131 0774662549 0043211173 2724723260 9487419156 9933646836 9125379223 5667134685 5222943258 8865004671 6141734722 7171201054 7631640362 4053094556 1001530711 1846561074 0541013350 9332750326 1168734558 5494776574 3707028780 3127582085 6451297928 3107355750 6032835005 6697408461 0578574122 9978595986 8449008429 0845821199 4850091655 2123240442 5475820337 5877358017 3224856824 2349530943 2982551303 1343403428 1870415607 4810035980 6692896000 9313955493 8371229804 0696832784 3122404273 2409004034 9976670757 0387606861 0830797119 9622718158 8190037544 3751685357 4921457521 5395349500 3092316506 6844694031 1007504323 0696778458 4764543607 6185902618 1680559034 3314718007 5917529843 5199364428 0017825448 1943581801 0497770381 9974784921 5419995433 4565074399 2156145472 3265461588 8657371701 6470286448 9527754997 1743036003 8267473010 3321823202 0918220922 7863294542 6818924758 5554576502 0406273122 9122206029 1743752110 7659429289 1495229550 8067652719 3736974763 1741222377 5678191405 6379457199 7681475381 2991379057 9831897873 6719085477 6856242415 1648543511 1210746901 2039302522 3889282473 3148863894 2074761511 9220488342 7143462084 1261065351 1698962078 1767613328 3743317695 5694504886 0710359468 8068384982 6704747585 8007394429 1767024212 6858115659 6450569183 4586219015 0090818316 8508484886 2172320275 5639070279 8547110903 4772585069 1656246767 5689627365 8008039321 1929395645 9799443856 6545455952 5530902166 7307888491 9237612811 9740388161 1624831318 0638065237 5362417559 8327874984 9098594591 0590849885 7922811409 9571987841

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) = 36.513282%

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 = 29 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 ≡ 61 (mod 64) and therefore cannot be a square and N is prime.