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 A138568 #4 May 07 2013 21:16:35 %S A138568 1,212,3212321,4321234321234,543212345432123454321, %T A138568 6543212345654321234565432123456, %U A138568 7654321234567654321234567654321234567654321 %N A138568 Erroneous duplicate of A136094. %K A138568 dead %O A138568 1,2 %A A138568 Aniruddha Das (hi.annie.pal(AT)gmail.com), May 18 2008