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 A215611 #15 Oct 12 2018 14:57:17 %S A215611 1,127,3473,19313,30353,226703,230777,345023,929783,1790159,1878073, %T A215611 2569337,3441743,4213511,8026103,9770153,19139183,24261623,30652223, %U A215611 35482433,38044223,40642103,55015793,65046479,67411121,69601193,119611073 %N A215611 Odd integers n such that 2^n == 2^8 (mod n). %C A215611 Also, the odd solutions to 2^(n-8) == 1 (mod n). The only even solution is n=8. %C A215611 For all m, 2^A051447(m)-1 belongs to this sequence. %H A215611 Max Alekseyev, <a href="/A215611/b215611.txt">Table of n, a(n) for n = 1..859</a> (all terms below 10^14) %t A215611 m = 2^8; Join[Select[Range[1, m, 2], Divisible[2^# - m, #] &], %t A215611 Select[Range[m + 1, 10^6, 2], PowerMod[2, #, #] == m &]] (* _Robert Price_, Oct 12 2018 *) %Y A215611 The odd terms of A015929. %Y A215611 Cf. A051447, A033984, A173572, A215610, A215612, A215613. %K A215611 nonn %O A215611 1,2 %A A215611 _Max Alekseyev_, Aug 17 2012