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 A000017 #7 Dec 11 1999 03:00:00 %S A000017 1,0,0,2,2,4,8,4,16,12,48,80,136,420,1240,2872,7652,18104,50184 %N A000017 Erroneous version of A032522. %K A000017 dead %O A000017 1,4