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 A027843 #2 May 11 2007 03:00:00 %S A027843 1,15,220,5275,151086 %N A027843 Duplicate of A027840. %K A027843 dead %O A027843 1,2