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 A113220 #6 Mar 30 2012 18:50:53 %S A113220 0,1,2,3,4,5,6,7,8,9,11,10,13,12,15,14,17,16,19,21,18,23,20,25,22,27, %T A113220 24,29,31,26,33,28,35,30,37,32,39,41,34,43,36,45,38,47,40,49,51,42,53, %U A113220 44,55,46,57,48,59,61,50,63,52,65,54,67,56,69,71,58,73,60,75,62,77,64,79 %N A113220 Inverse of A113218. %C A113220 Permutation of the natural numbers. %H A113220 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %K A113220 nonn %O A113220 0,3 %A A113220 _Reinhard Zumkeller_, Oct 18 2005