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 A080781 #3 May 11 2007 03:00:00 %S A080781 1,5,9,13,12,16,20,24,23,27,31,30,29,33,37,36,40,44,48,47,51,55,54 %N A080781 Duplicate of A079357. %K A080781 dead %O A080781 1,2