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 A031001 #4 Mar 30 2012 18:56:19 %S A031001 2,12,21,23,25,26,27,29,31,33,40,54,68,82,99,120,134,137,140,141,143, %T A031001 146,149,152,162,183,204,225,238,241,244,246,247,250,253,256,259,262, %U A031001 265,267,268,271,274,277,280,281,283,284,286 %N A031001 Position of n-th 2 in A030998. %K A031001 nonn %O A031001 1,1 %A A031001 _Clark Kimberling_