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 A031222 #4 Mar 30 2012 18:56:21 %S A031222 2,10,15,17,19,20,21,23,30,40,53,68,76,79,82,83,85,88,98,113,120,123, %T A031222 126,128,129,132,135,138,141,143,144,147,150,151,153,154,156,157,158, %U A031222 159,160,162,163,165,168,171,173,174,177,180 %N A031222 Position of n-th 2 in A031219. %K A031222 nonn %O A031222 1,1 %A A031222 _Clark Kimberling_