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 A121664 #13 Sep 05 2017 03:59:47 %S A121664 1,2,3,5,4,6,11,10,9,7,8,12,23,22,21,19,20,18,13,14,15,17,16,24,47,46, %T A121664 45,43,44,42,37,38,39,41,40,36,25,26,27,29,28,30,35,34,33,31,32,48,95, %U A121664 94,93,91,92,90,85,86,87,89,88,84,73,74,75,77,76,78,83,82,81,79,80,72 %N A121664 Inverse permutation to A096114. %H A121664 Ivan Neretin, <a href="/A121664/b121664.txt">Table of n, a(n) for n = 1..12288</a> %H A121664 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %Y A121664 Inverse: A096114. %K A121664 nonn %O A121664 1,2 %A A121664 _Antti Karttunen_, Aug 25 2006, based on _Amarnath Murthy_'s comments on A096114