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 A271501 #3 Apr 16 2016 11:58:32 %S A271501 1,6,255,92263,280864514 %N A271501 Erroneous version of A113900. %K A271501 dead %O A271501 1,2