This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A357125 #12 Feb 08 2025 18:34:22 %S A357125 1,5,4553,46777,82505,4290773,4492205,4976429,21537833,21549349, %T A357125 51127261,56786089,60296573,80837773,87761789,94424465,138644873, %U A357125 168865001,221395541,255881453,297460453,305198249,360306365,562654205,635374253,673867253,808333573,1164757553,1210317349 %N A357125 Positive integers n such that 2^(n-3) == -1 (mod n). %C A357125 Also, odd integers n dividing 2^n + 8. %C A357125 Some large terms: 5603900696716667005, 446661376165868432471569407934747098747181600670953926245, 1533278864164902082788937853692280620552397221686019535813. %H A357125 Max Alekseyev, <a href="/A357125/b357125.txt">Table of n, a(n) for n = 1..781</a> (all terms below 10^15) %t A357125 Select[Range[2155*10^4],PowerMod[2,#-3,#]==#-1&]//Quiet (* The program generates the first 10 terms of the sequence. *) (* _Harvey P. Dale_, Feb 08 2025 *) %Y A357125 The odd terms of A245319. %Y A357125 Cf. A006521, A115976, A276967, A251603. %K A357125 nonn %O A357125 1,2 %A A357125 _Max Alekseyev_, Sep 13 2022