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 A291746 #9 Sep 08 2022 08:46:19 %S A291746 1,6,16,21,26,36,46,51,56,66,76,81,86,91,96,106,111,116,121,126,136, %T A291746 141,146,156,161,166,171,176,186,196,201,206,216,221,226,231,236,246, %U A291746 256,261,266,276,286,291,296,301,306,316,321,326,336,341,346,351,356,361,366,371 %N A291746 Nonprimes of the form 5*k + 1. %C A291746 Subsequence of A018252. %t A291746 DeleteCases[5 Range[0, 200] + 1, _?PrimeQ] %o A291746 (Magma) [n: n in [1..400 by 5] | not IsPrime(n)]; %Y A291746 Cf. A016861, A030430, A091113, A091300, A291745, A291747. %K A291746 nonn,easy %O A291746 1,2 %A A291746 _Vincenzo Librandi_, Aug 31 2017