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 A215613 #12 Oct 15 2018 11:44:03 %S A215613 1,23,89,2047,5969,1803407,6531977,6667079,7694041,16252897,146825647, %T A215613 284464633,315096487,351745417,413414167,512694047,615366953, %U A215613 2723423687,3104303327,3969298807,5754671737,7242954137,8766711119,14046374879 %N A215613 Odd integers n such that 2^n == 2^12 (mod n). %C A215613 Also, the odd solutions to 2^(n-12) == 1 (mod n). The only even solution is n=12. %C A215613 For all m, 2^A051446(m)-1 belongs to this sequence. %H A215613 Max Alekseyev, <a href="/A215613/b215613.txt">Table of n, a(n) for n = 1..93</a> (all terms below 10^14) %t A215613 m = 2^12; Join[Select[Range[1, m, 2], Divisible[2^# - m, #] &], Select[Range[m + 1, 10^7, 2], PowerMod[2, #, #] == m &]] (* _Robert Price_, Oct 15 2018 *) %Y A215613 The odd terms of A015937. %Y A215613 Cf. A173572, A033984, A215610, A215611, A215612 %K A215613 nonn %O A215613 1,2 %A A215613 _Max Alekseyev_, Aug 17 2012