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 A039668 #1 Dec 11 1999 03:00:00 %S A039668 1,0,6,5,20,17,56,45,156,115,344,85,356,125 %N A039668 Replaced by the pair of sequences A048611 and A048612. %K A039668 dead %O A039668 0,3