Primality Certificate for (20250^4099-1)/20249

Andy Steward17,648 digits13 February 2010
Originally by A.A.D.Steward 2010

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 33.607568% factorization of N-1:

From Factorisation
202502 · 3 · 3 · 3 · 3 · 5 · 5 · 5
Φ27 · 11 · 263
Φ313 · 31544827
Φ637 · 11082223
Φ683313387721 · 293992220671 · c2918
Φ13661367 · c2934
Φ2049p5874
Φ40984099 · 28687 · c5866

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 :

9198 4813460248 9819264299 5304414837 1861704668 3712284213 2986550112 8716308214 6599023632 8697279865 3756810876 9718994481 9954522749 7436159995 3425264420 4522381712 4410662684 6686891393 9586988163 1950135705 8706054267 1695752211 8413845984 8552173675 0253355552 2234373586 7488774781 1090020708 3964465160 4219236414 7203218484 1579033364 8274783535 7845123839 1707126854 9023347208 0118788667 4546347863 6178927600 0458848833 1868171509 8736277718 5868050265 8348806486 6428906297 7550973265 1531266242 7345532674 7494147673 4377444485 4241613423 6407959111 9342924170 2199330963 1259658866 4813251674 2881074007 7428587487 9205580440 3569982484 4461741439 7127824033 7790935690 0777196302 0383054047 8442279758 3503438191 3786814675 5763220928 5861166295 0025968385 0901149190 0547982395 8795289756 9358258719 0977473152 4147837838 6814907710 8212307714 5289385403 9868470821 6143288655 9771343851 2158118533 6198918609 8697020787 2652769067 3333198225 6931815380 4118320800 1204631274 8282844544 4592658862 2002641671 9446330031 2330051361 6896016608 1404485722 8192797254 2281457947 6582454559 9347488335 4271461165 0808718947 6702453592 2025957180 5875084061 3945428312 0534088972 1512901601 0395464238 0450507994 9674851861 7355089661 2546424321 1818784278 5604676939 3066867394 6491906815 5482080553 8959638200 4429276291 0004740416 5814071829 2260137931 3654797113 6254117317 7541068694 4693338066 1511960559 3413623405 9192221142 0835051392 5326270503 8941057463 9835273936 5949468762 5821503449 1695929709 4296737242 3166651707 7033590894 7505373776 9961800476 4836195388 7654369389 5717371062 8147977340 3365649503 5695121798 9363204324 8835814890 0437452888 3953884290 7210649692 8054548309 3490092761 2689625231 0838483724 3489964287 3138152670 9041321195 1751271538 2070576514 2917863332 3743571061 5076229992 2616823161 1351572503 9503412172 4537800350 3045247115 8778241153 1081627960 5826191496 2877416718 9329390239 9288841343 1158373944 5608574529 0970540202 3862359727 7230078439 6211566490 7877586598 4414007182 8910704509 3032906567 0024445187 1286833233 5573792152 6169332326 8145592210 8877578501 2456465280 4258011371 2494336978 6321396743 3498233763 7524185414 0536144212 3826196804 6035426764 1125434703 7581386883 9205024380 8816839377 7509284670 6977669768 3686916116 1661290356 1434821829 6415000986 5143860435 5218993260 4344510215 3350690679 4736595603 4901218160 1853317709 4787947135 2400440143 6089723185 8434211727 3227697373 3183869347 3029467762 4042923735 2134788327 1186658532 4918280631 5644160353 4661853227 9545451950 1357241044 9606912867 3813612973 5341786108 1201778984 9883919150 8442663218 9821751399 9883275834 5883124844 5926667034 8798084873 1706383583 7719542442 8730488051 9422736831 4824023961 9576959610 1685195917 6608674655 4867124337 8514849311 6656668244 5860892128 3677859491 5110596786 0871866052 9028728741 6987995578 7935613438 0060141545 8571873353 2956620052 5447228853 9257395691 8488825516 5872991377 8935732962 4502756307 5612258029 2713031120 6448010767 8880792006 5201243171 3962988888 3658885456 8342307637 2148256265 6574108025 8540982949 5879518344 4103369155 6879841901 9517769026 7279957926 4459013424 7996473128 9760047127 4939324349 1445540605 6743167166 7951317272 0541618815 3944486600 7533696848 2626627329 3901758297 3086027059 3058472231 8375696639 3254103616 1639502613 3298515257 5904268527 5365981381 3772935700 2247545521 2566619861 6003933786 0896794971 7954405744 8950268183 6913540011 6080271307 4330412016 5327800103 6690489826 4790655357 9798101222 0429669803 2579410198 7817782858 7018866714 1904301088 2280708481 9482662229 1714262798 5065151608 3880672087 4360578278 2526704776 9815080116 5023114446 6492561081 7846428593 5733080048 8014630318 1706172720 4930569896 6897407580 0696735731 1477948902 2457422507 8085345296 8411174021 8742981900 4802822819 5823141773 1228303920 7263506764 6250973044 8717546957 3152140356 3042453316 1676426872 6096914207 4449680723 6408421658 6032082234 7687913816 2858380819 6395374882 3952184569 5025061634 4156560361 9901505967 8845352764 5017601628 6810801706 0991807513 4456526379 6283981315 1505794713 7774527991 0071797125 1654113517 3087557078 6489587126 9589543946 6031800556 0874347099 8848792200 0795737163 5113392883 5836529165 2503042906 8496632123 1709292987 0096541379 4289759271 5264170601 4647831550 6513307565 4832919558 9017468283 7718229255 5844070232 6096613660 1321064349 8965745381 8365009278 1126197340 4334412556 6952039054 7750143843 2316275666 4588880510 2892880649 4608603626 4074827496 5693820394 6934945528 9487319046 0463490583 0911469633 2467361421 9206367189 0071633705 7731672147 4800428118 8475892966 1267994168 9730649038 1888145838 4094274849 6014806354 9725090697 9131700788 0498226435 0468259199 4310452492 7094849445 4047721365 3421201371 3921397497 5120326906 8960657757 2862973951 8541110258 2955439047 1765343108 2720546514 5340771415 1779963684 1892811349 1687855705 4531440769 2962725436 3013085079 6111980428 6097251146 7869657350 4403687339 8838055838 2792213582 6297613234 0232836555 1620932972 9842843238 5422009376 7745238056 7164149488 8283303097 2880241510 9283248048 3484804028 6731138443 4909915528 5865215665 7088726319 2508778130 4011622202 0918645044 7683693634 3448852290 6809169021 5368486975 0110582499 5839944600 4195348695 6642962926 0778200690 5731078116 0876891148 9369860789 3383054517 7690325607 4555701544 1399971766 6921083227 6142249933 4824598127 3792611847 8617146549 9706628018 0309626636 6223488827 4381296706 8800299827 0672067881 0046917824 1535764692 5987713580 1762957177 9698987802 1385695899 9520573459 8292983034 0485929069 1268792038 0880916868 8253050797 1870426940 2012282088 3583562889 4657975713 7008305916 2856620614 1160031381 0809370033 7081478464 8184336824 2523324274 1292476356 8024347359 1016755542 5904758427 6472043077 9591604914 8821672823 7857534271 1744537628 6992378277 3296894899 1468309770 4833725132 7110805496 9129876911 1115331939 4309271983 9854956493 8906684226 7647585108 9869420038 1034802412 3550614787 9894611807 2642367735 1891350338 7027366093 7277510606 6336352684 0952156995 2597201534 0874456823 9594159374 9208924907 9388857299 1942301908 7189063458 0726366615 6980106680 9562053489 0529935993 3332089844 4714149900 9306051012 1285252497 7330733913 2632769526 0706051984 1274669950 6997796159 4390494127 3669908637 5374027862 9763679087 2971879765 7987814269 2229452001 5059106936 1998110474 0491755040 9234354751
29 3992220671

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) = 33.349514%

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 = 3 suffices.

Given such a witness, Pocklington's Theorem shows that every prime factor of N ≡ 1 (mod F). As F3>N, N can have no more than two prime factors.

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

Brillhart, Lehmer and Selfridge's Theorem shows that N is prime if and only if c12-4·c2 is not a square (given 2F3 > N).

Here, c12-4·c2 is ≡ 40 (mod 64) and therefore cannot be a square and N is prime.