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 A231565 #7 Jan 16 2014 10:08:17
%S A231565 2,4,6,8,12,16,18,20,24,30,32,36,40,42,48,54,60,64,66,72,80,84,90,96,
%T A231565 100,102,108,110,120,126,128,132,138,140,144,150,156,160,162,168,174,
%U A231565 180,192,198,200,204,210,216,220,240,246,252,256,260,264,270,272
%N A231565 Numbers such that A231563(n)>0.
%t A231565 S[n_] := Mod[Sum[If[GCD[i, n] == 1, PowerMod[i, n, n], 0], {i, 1, n}], n]; Select[Range[1200], ! S[#] == 0 &]
%Y A231565 Cf. A231563, A231564.
%K A231565 nonn
%O A231565 1,1
%A A231565 _José María Grau Ribas_, Dec 09 2013