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 A091300 #23 Oct 06 2024 09:31:31
%S A091300 1,25,49,55,85,91,115,121,133,145,169,175,187,205,217,235,247,253,259,
%T A091300 265,289,295,301,319,325,343,355,361,385,391,403,415,427,445,451,469,
%U A091300 475,481,493,505,511,517,529,535,553,559,565,583,589,595,625,637,649
%N A091300 Nonprimes of the form 6k + 1.
%D A091300 R. K. Guy, Unsolved Problems in Number Theory, Springer, 1st edition, 1981. See section D1.
%H A091300 Nathaniel Johnston, <a href="/A091300/b091300.txt">Table of n, a(n) for n = 1..10000</a>
%p A091300 for k from 0 to 100 do if(not isprime(6*k+1))then printf("%d, ",6*k+1); fi: od: # _Nathaniel Johnston_, May 18 2011
%t A091300 Do[If[ !PrimeQ[n]&&Equal[Mod[n, 6], 1 ], Print[n]], {n, 1, 1000}]
%t A091300 DeleteCases[6*Range[0,150]+1,_?PrimeQ] (* _Harvey P. Dale_, Jun 23 2014 *)
%o A091300 (GAP) Filtered(List([0..110],k->6*k+1),n->not IsPrime(n)); # _Muniru A Asiru_, Mar 12 2019
%o A091300 (Sage) [n for n in (1..650) if ((n-1)/6).is_integer() and not is_prime(n)] # _Stefano Spezia_, Oct 05 2024
%Y A091300 Cf. A091113, A092256.
%Y A091300 Cf. A002476. Subsequence of A016921.
%K A091300 easy,nonn
%O A091300 1,2
%A A091300 _Labos Elemer_, Feb 24 2004