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 A139314 #23 Sep 08 2022 08:45:33 %S A139314 7,31,8191,2305843009213693951 %N A139314 Primes of the form 2^(2p - 1) - 1, where p is prime. %C A139314 Primes in A139287. %C A139314 This sequence is a subsequence of A000668. From A000043, a(5) = 2^3217 - 1. %C A139314 The next term a(6) is an unknown Mersenne prime. [_Washington Bomfim_, Nov 18 2009] %C A139314 a(5) has 969 digits. - _Vincenzo Librandi_, Dec 14 2010 %C A139314 The first three terms can be written as (n^3 - 1)/(n - 1) for some n. [_Arkadiusz Wesolowski_, May 09 2012] %H A139314 Michel Marcus, <a href="/A139314/b139314.txt">Table of n, a(n) for n = 1..5</a> %H A139314 Wikipedia, <a href="https://en.wikipedia.org/wiki/Mersenne_prime">Mersenne prime</a> %o A139314 (Magma) [a: p in PrimesUpTo(4200) | IsPrime(a) where a is 2^(2*p-1)-1]; // _Vincenzo Librandi_, Dec 14 2010 %Y A139314 Cf. A139286, A139287. %Y A139314 Cf. A000668, A000043. [_Washington Bomfim_, Nov 18 2009] %K A139314 nonn %O A139314 1,1 %A A139314 _Omar E. Pol_, Apr 13 2008