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 A123408 #13 Dec 01 2015 15:04:24 %S A123408 1,2,3,7,13,35,88,303,1119,5479 %N A123408 Duplicate of A033995. %K A123408 dead %O A123408 1,2