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 A036399 #8 Mar 04 2021 11:23:27 %S A036399 12,66,312,1368,5685 %N A036399 Duplicate of A003200. %K A036399 dead %O A036399 1,1