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 A090638 #4 Jan 09 2009 03:00:00 %S A090638 0,1,1,2,3,3,4,4,5,6,6,7,8,8,9,9,10,11,11,12,12,13,14,14,15,16,16,17, %T A090638 17 %N A090638 Duplicate of A073869. %K A090638 dead %O A090638 1,4