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 A016108 #15 May 26 2024 01:03:13
%S A016108 1,31,43,109,127,157,223,229,277,283,307,397,433,439,457,499,601,643,
%T A016108 691,727,733,739,811,919,997,1021,1051,1069,1093,1327,1399,1423,1459,
%U A016108 1471,1579,1597,1627,1657,1699,1723,1729,1753,1777,1789,1801,1831,1933,1999,2017,2047,2089,2113,2143,2179,2203
%N A016108 Numbers k=3*m+1 such that 2^m == 1 (mod k).
%C A016108 Prime terms are listed in A014752.
%H A016108 Harvey P. Dale, <a href="/A016108/b016108.txt">Table of n, a(n) for n = 1..1000</a>
%t A016108 Join[{1},Select[Table[3m+1,{m,1000}],PowerMod[2,(#-1)/3,#]==1&]] (* _Harvey P. Dale_, Apr 26 2016 *)
%Y A016108 Cf. A014752.
%K A016108 nonn
%O A016108 1,2
%A A016108 _Max Alekseyev_, Jun 23 2012