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 A056209 #3 May 11 2007 03:00:00 %S A056209 53,173,277,317,397,769,773,797,809,853,1009,1013,1093,1493,1613,1637 %N A056209 Duplicate of A056157. %K A056209 dead %O A056209 1,1