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 A163906 #4 Mar 31 2012 13:21:18 %S A163906 0,1,2,3,12,15,13,14,7,4,5,6,9,11,8,10,16,19,17,18,20,21,22,23,27,25, %T A163906 26,24,30,29,28,31,47,44,45,46,39,37,38,36,40,41,42,43,34,33,35,32,58, %U A163906 56,59,57,54,53,52,55,49,50,48,51,60,61,62,63,192,195,193,194,196,197 %N A163906 Permutation A163356 applied twice. %H A163906 A. Karttunen, <a href="/A163906/b163906.txt">Table of n, a(n) for n = 0..16383</a> %H A163906 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %Y A163906 Inverse: A163905. a(n) = A163356(A163356(n)). See also A163916. %K A163906 nonn %O A163906 0,3 %A A163906 _Antti Karttunen_, Sep 19 2009