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 A113325 #6 Mar 30 2012 18:50:53 %S A113325 1,2,3,4,5,6,10,12,8,9,11,7,20,14,22,24,16,17,18,30,32,13,34,23,15,40, %T A113325 26,42,44,28,29,31,19,52,21,54,35,36,37,38,62,64,25,66,43,27,72,46,74, %U A113325 76,48,49,50,82,84,33,86,55,56,57,58,94,96,60,61,63,39,104,41,106,67,68 %N A113325 A113324(A113324(n)). %C A113325 Inverse integer permutation of A113323; %C A113325 A113321(a(n)) = a(A113321(n)) = A113324(n). %H A113325 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %K A113325 nonn %O A113325 1,2 %A A113325 _Reinhard Zumkeller_, Oct 26 2005