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 A031010 #4 Mar 30 2012 18:56:19 %S A031010 2,11,22,24,25,26,28,30,32,34,39,53,67,81,97,118,134,137,139,140,143, %T A031010 146,149,152,160,181,202,223,240,243,244,246,249,252,255,258,261,264, %U A031010 265,267,270,273,276,279,281,282,284,285,286 %N A031010 Position of n-th 2 in A031007. %K A031010 nonn %O A031010 1,1 %A A031010 _Clark Kimberling_