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 A171925 #2 Mar 30 2012 17:28:13 %S A171925 2,3,5,9,13,24,48,72,119,220,348,407,587,797,1125,1555,1847,2581,3560, %T A171925 3571,3690,4982,6739,7134,9429,11659 %N A171925 Positions of 2's in A171922. %K A171925 nonn,more %O A171925 1,1 %A A171925 _Hugo van der Sanden_, Oct 23 2010, Oct 24 2010