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 A147676 #2 Mar 30 2012 16:51:02 %S A147676 90,100,50,60,30,40,20,30,15,25 %N A147676 Add 10, divide by 2, repeat. %C A147676 A147675-A147678 are from a quiz that someone asked me to help them with. %K A147676 nonn,fini,full %O A147676 1,1 %A A147676 _N. J. A. Sloane_, Apr 21 2009