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 A063239 #43 Feb 18 2023 08:28:15 %S A063239 3,7,13,17,23,27,33,37,43,47,53,57,63,67,73,77,83,87,93 %N A063239 Duplicate of A063226. %K A063239 dead %O A063239 1,1