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 A047756 #3 May 11 2007 03:00:00 %S A047756 0,0,1,2,2,7,12,29,55,143,271,728,1428,3873,7752,21318,43256,120175 %N A047756 Duplicate of A047767. %K A047756 dead %O A047756 0,4