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 A229021 #6 Sep 13 2013 03:32:21 %S A229021 5,7,23,389,409,1511,5309,7351,37223,142811,763271,8066923,9182389, %T A229021 10237391,24374033,70353383,128463691,334100083,358453847,610611193 %N A229021 Record values in A226657. %Y A229021 Cf. A000230, A133429, A133430, A226657, A229028, A229030, A229033, A229034. %K A229021 nonn,more %O A229021 1,1 %A A229021 _Arkadiusz Wesolowski_, Sep 11 2013