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 A050109 #4 Mar 30 2012 18:57:01 %S A050109 1,9,13,17,2,4,6,8,25,10,27,12,29,85,14,31,87,16,74,18,89,117,48,104, %T A050109 3,91,119,50,78,5,22,93,121,581,7,80,108,24,39,95,123,421,54,192,26, %U A050109 110,138,41,69,11,125,315,56,153,28,84,112,140 %N A050109 a(n)=position of n in A050108. %K A050109 nonn %O A050109 1,2 %A A050109 _Clark Kimberling_