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 A030572 #4 Mar 30 2012 18:56:18 %S A030572 4,14,26,38,43,45,47,49,50,51,53,62,78,96,114,132,139,142,145,148,150, %T A030572 151,154,168,186,204,222,240,247,250,253,256,258,259,262,276,294,312, %U A030572 330,348,355,358,361,364,366,367,370,384,392 %N A030572 Position of n-th 4 in A030567. %K A030572 nonn %O A030572 1,1 %A A030572 _Clark Kimberling_