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 A056837 #4 May 11 2007 03:00:00 %S A056837 0,0,1,1,2,3,5,6,8,10,13,15,18,21,25,28,32,36,41,45,50,55,61,66,72,78 %N A056837 Duplicate of A001971. %K A056837 dead %O A056837 0,5