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 A123423 #7 Dec 04 2015 14:13:42 %S A123423 1,2,3,6,10,20,37,76,153,329 %N A123423 Duplicate of A005195. %K A123423 dead %O A123423 1,2