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 A047833 #1 Dec 11 1999 03:00:00 %S A047833 1,3,10,70,708,15248,543520 %N A047833 Erroneous version of A002499. %K A047833 dead %O A047833 1,2