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 A231564 #8 Oct 05 2023 10:58:00
%S A231564 1,3,5,7,9,10,11,13,14,15,17,19,21,22,23,25,26,27,28,29,31,33,34,35,
%T A231564 37,38,39,41,43,44,45,46,47,49,50,51,52,53,55,56,57,58,59,61,62,63,65,
%U A231564 67,68,69,70,71,73,74,75,76,77,78,79,81,82,83,85,86,87,88
%N A231564 Numbers such that A231563(n)=0.
%C A231564 This sequence contains the odd primes.
%t A231564 S[n_] := Mod[Sum[If[GCD[i, n] == 1, PowerMod[i, n, n], 0], {i, 1, n}], n];Select[Range[100],S[#]==0&]
%Y A231564 Cf. A231563, A231565.
%K A231564 nonn
%O A231564 1,2
%A A231564 _José María Grau Ribas_, Dec 09 2013