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 A047840 #4 Jan 09 2009 03:00:00 %S A047840 0,0,3,4,6,4,13,13,7,16,8,23,36,58,62,99,172,281 %N A047840 Incorrect version of A037189. %K A047840 dead %O A047840 1,3