Primality Certificate for (2389^3769-1)/2388

Andy Steward12,730 digits26 June 2008
Originally by A.A.D.Steward 2008

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 35.061957% factorization of N-1:

From Factorisation
23892389
Φ22 · 5 · 239
Φ33 · 7 · 97 · 2803
Φ42 · 2853661
Φ613 · 13 · 33757
Φ82 · 17 · 275881 · 3472673
Φ12577 · 56453218873
Φ241061033748968366376561758641
Φ1571571 · 5653 · c521
Φ31442391 · 156560087 · 46634904457 · c504
Φ47169709 · 24679171078607029 · 51794079985765651 · c1017
Φ628102122221 · 252749643038369 · c1032
Φ9428474757637 · 42755782369 · 1953296472229 · c1022
Φ12561977622839875285017 · c2090
Φ18841096891546715285059938721 · c2084
Φ37683769 · 15073 · 7375679137 · 252546695496809873563441 · p4175

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 :

97540 5826705431 3931363939 8336132178 4169969590 3397625535 9234605856 9176116766 2624342884 0350714515 9433433885 8981789110 7413434267 3006299141 0343303841 2227957670 2586364813 4088690612 3510721230 1993798247 1265572824 9882674227 8057293619 9808123603 4810710561 9897170963 0404010091 2930515713 4070046361 8347926508 5753414754 9712603001 7157130847 3025435020 2688444792 3293994838 8691314957 0419751417 2744358314 8408052838 4235176926 1968090984 6004243759 5472533488 3192558636 3819502860 7994738111 6272942156 3710826170 6034114523 4178581369 8018963245 4114097478 2027390314 0338908942 6295673026 7811323609 4905059369 1328622147 9354535625 0312085350 4641989537 4058782938 0284713038 8390869767 1545968436 6980894251 4022079956 7596525065 8557970223 7590060434 5389868581 5565429725 0609894471 0440956867 7685376149 8418012325 9427864696 0683686258 8987223523 4961864464 5584363301 7194518983 7046003754 4344883537 1251162466 0767614677 6714956327 9291325295 7273159443 2074332971 4795228155 7355092359 1099126101 3442346313 5763668588 1740815123 4554140970 1406588359 0301076588 9001406981 7700274889 0301960432 1533928018 0987774678 5504889020 4561299701 1054884019 4683626184 2431080367 6843742229 6198454816 4228680503 5185519718 1908825384 7446394843 9962629704 4802436137 1636424266 5123533263 7154645678 0455869164 7472197755 3021468662 3632489358 7964899538 0073090686 4938465518 4541016375 1107214428 6458740912 3355292629 8425882519 5268290380 2651329108 6964656940 8057328992 4526019924 6307627692 2536819669 3695558730 5658952114 1942825151 5829123531 8836958586 4885233944 8785906628 1327151687 6229767508 1663691188 8259504937 9240794253 7665511712 4637571671 3051071129 3736911561 9084157014 5087239762 0569600661 2520151640 2901312335 2249445756 6678118900 3153154519 3749744823 2729584512 5927206074 1164364234 2019551987 0349779229 0231570416 6613153676 4442648754 6574789820 8489730331 6839037826 2974501208 0827702799 0108327185 7821939909 7744322100 6224879848 1840777716 3657896188 8909407557 1475149641 0388229422 3431771979 4732508439 1930393957 6689478145 9416548912 2641637648 3340713316 9040128713 5262159883 4485992808 7108315677 7273769322 0156861104 2775860546 8077454505 7498005718 9847024041 2033225339 1778227521 1686286292 8614614097 3955950824 0102611654 3598504363 6405689843 5882170435 7063216519 7893385362 1458031431 8997470726 1416083047 6718158876 8032624087 6595755517 7758690890 0290872059 3162575895 7823914400 0159185249 2366114911 0623235129 4764835753 8111308640 9158982991 8605649781 5902755316 1434677101 5938074744 7900711061 2676410719 5413073613 8649921091 2773120656 7009378155 5516377566 8087475677 6986915357 3280088792 0989934380 0796710577 6113957235 3103647001 7072550443 1825443725 2859593777 4522261625 6516635279 1925170050 2707188711 6366771932 8914064215 0519343223 7291885915 4508860895 0394304347 2575238284 2548485420 3131885652 5890720325 6092877290 2562266034 6594302393 3975712732 1443816610 7434800013 1248157952 1016371342 9858096567 5729592299 2944862421 6771421187 9249404561 7717814334 3217801088 0412431462 6329913071 8456051229 7226988213 5845537380 1041526904 1211622242 6524455127 8969106729 4256673765 0912205276 2016520218 1469313871 3648503119 9787876493 8601075121 5283250710 5617555851 0133168803 8078140878 8071911961 5871245076 0039671800 5373219238 8960899259 1160085590 9424493522 3089450083 6438578119 3070200253 4735144661 0564873572 2080409802 4030201596 8347052995 5366671573 5285813233 2605487161 9361427923 5830763507 7823387058 6893689448 0232724049 6077418616 4773776780 3520559899 2002409655 2332271755 3144569876 1578727750 4577367972 2594685339 2040322437 2431228398 4571885761 5186728445 0590825661 4174841859 6734977834 0310992184 4666752333 3421112995 4539414400 4332939679 4138052672 5546251133 6941188467 9136260839 7635762702 3938078813 5234417738 0675871826 5633675229 7298421672 4139968748 5551615503 3145278324 5496437555 6410564842 0311980093 6870057541 4015471780 3589418339 0847479217 9085050717 5713345297 6748151654 2971435792 1642109031 1679981488 3583714865 4744734411 7819137619 6958942284 1635655205 9565033758 5735064954 0052337847 4686341974 6427202644 9598739759 0943375189 8076757838 7483576753 1005830779 6356867210 9290974980 0465365722 4710105809 5691927636 5856880725 0708507112 1259034379 3053683141 9055745978 7531809133 2643112122 3148931989 8732072855 8292004110 3586722967 1790071727 5262262476 8380073777 1328416689 2397368722 1844630751 1786671812 2882179421 3587076203 8353010859 9739214885 9067319219 8167017990 2498153904 2118226871 4716088729
10610337 4896836637 6561758641
10968 9154671528 5059938721
2525 4669549680 9873563441

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) = 33.383752%

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 = 31 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 ≡ 44 (mod 64) and therefore cannot be a square and N is prime.