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 A071662 #9 Jun 23 2017 08:57:43
%S A071662 0,1,2,3,4,7,5,6,8,9,17,12,16,21,10,18,11,14,20,13,15,19,22,23,45,31,
%T A071662 44,58,26,49,30,42,57,35,43,56,63,24,46,32,47,59,25,48,28,37,54,34,40,
%U A071662 53,62,27,50,29,38,55,33,39,51,61,36,41,52,60,64,65,129,87,128,170,73
%N A071662 Permutation A057506 applied twice ("squared").
%H A071662 A. Karttunen, <a href="http://www.iki.fi/~kartturi/matikka/Nekomorphisms/gatomorf.htm">Gatomorphisms</a> (Includes the complete Scheme source for computing this sequence)
%H A071662 Indranil Ghosh, <a href="/A071662/a071662.txt">Python Program for computing this sequence</a>
%H A071662 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%Y A071662 Inverse permutation: A071661 and also its car/cdr-flipped conjugate, i.e. A071662(n) = A057163(A071661(A057163(n))) = A057506(A057506(n)). Cf. also A071664, A071666, A071668, A071670.
%K A071662 nonn
%O A071662 0,3
%A A071662 _Antti Karttunen_, May 30 2002