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 A163905 #5 Dec 18 2015 18:14:46 %S A163905 0,1,2,3,9,10,11,8,14,12,15,13,4,6,7,5,16,18,19,17,20,21,22,23,27,25, %T A163905 26,24,30,29,28,31,47,45,44,46,39,37,38,36,40,41,42,43,33,34,35,32,58, %U A163905 56,57,59,54,53,52,55,49,51,48,50,60,61,62,63,149,150,151,148,152,154 %N A163905 Permutation A163355 applied twice. %H A163905 A. Karttunen, <a href="/A163905/b163905.txt">Table of n, a(n) for n = 0..65535</a> %H A163905 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %Y A163905 Inverse: A163906. a(n) = A163355(A163355(n)). Array A163907 shows this in N x N grid. See also A163915. %K A163905 nonn %O A163905 0,3 %A A163905 _Antti Karttunen_, Sep 19 2009