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 A087113 #9 Feb 09 2012 18:57:09 %S A087113 2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48 %N A087113 Essentially a duplicate of A005843. %K A087113 dead %O A087113 1,1