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 A163915 #15 Jan 10 2021 05:55:08 %S A163915 0,1,3,2,7,5,6,4,9,8,10,11,14,13,12,15,16,17,18,19,20,21,23,22,28,29, %T A163915 31,30,27,25,24,26,48,51,50,49,52,53,55,54,60,61,63,62,57,59,56,58,47, %U A163915 46,45,44,39,37,36,38,35,34,32,33,40,41,43,42,127,125,126,124,118,117 %N A163915 Permutation A163355 applied thrice. %H A163915 Antti Karttunen, <a href="/A163915/b163915.txt">Table of n, a(n) for n = 0..65535</a> %H A163915 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A163915 a(n) = A163355(A163355(A163355(n))) = A163355(A163905(n)). %Y A163915 Inverse: A163916. Array A163917 shows this in N X N grid. See also A163905. %Y A163915 Cf. A163355 %K A163915 nonn %O A163915 0,3 %A A163915 _Antti Karttunen_, Sep 19 2009