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 A016048 #20 Jun 09 2023 21:42:06 %S A016048 1,3,9,1,315,3855,13797,1,4,34636833,3,163,5,25,60,1525, %T A016048 18900352534538475,1445580,1609,3,17,1,3477359660913989536233495,59, %U A016048 36793758459,12379533,758220919762679268184943973309,3421967,15 %N A016048 Least k such that (2*p_n)*k + 1 | Mersenne(p_n), p_n = n-th prime, n >= 2. %C A016048 M(p_n) = 2^p_n - 1 = (2*p_n)*j + 1 = [(2*p_n)*k_1 + 1] ... [(2*p_n)*k_i + 1], n >= 2 (i.e., odd prime p_n), i >= 1. Then k = Min(k_1, ..., k_i). %H A016048 Chris K. Caldwell, <a href="https://t5k.org/notes/proofs/MerDiv.html">Modular restrictions on Mersenne divisors</a> %F A016048 a(n) = (A016047(n) - 1) / (2*A000040(n)). - _Jeppe Stig Nielsen_, Jul 18 2014 %Y A016048 Cf. A000040, A016047. %K A016048 nonn %O A016048 2,2 %A A016048 _Robert G. Wilson v_ %E A016048 Definition edited, comment added by _Daniel Forgues_, Oct 06 2009