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 A069967 #3 May 11 2007 03:00:00 %S A069967 1,2,3,10,11,12,13,20,21,22,30,31,100,101,102,103,110,111,112,113 %N A069967 Duplicate of A061909. %K A069967 dead %O A069967 0,2