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 A026258 #4 Mar 30 2012 18:56:05 %S A026258 1,2,5,3,4,6,9,10,11,14,7,8,17,19,20,21,12,13,15,26,28,29,30,16,18,34, %T A026258 37,39,40,22,23,24,44,47,49,50,25,27,54,55,58,60,31,32,33,64,65,68,35, %U A026258 36,38,72,73,74,77,41,42,43,81,82,83,45,46 %N A026258 Position of n in A026257. %K A026258 nonn %O A026258 1,2 %A A026258 _Clark Kimberling_