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 A272169 #19 Nov 29 2020 04:03:18 %S A272169 7,5,2,0,1,0,7,4,2,3 %N A272169 Duplicate of A084911. %K A272169 dead %O A272169 0,1