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 A071666 #5 Apr 30 2014 01:53:48
%S A071666 0,1,2,3,4,6,7,5,8,9,14,16,11,19,17,20,12,10,15,21,18,13,22,23,37,42,
%T A071666 28,51,44,53,30,25,39,56,48,33,60,45,54,57,34,61,31,40,26,24,38,43,47,
%U A071666 29,52,58,62,49,46,55,35,32,27,41,63,59,50,36,64,65,107,121,79,149,126
%N A071666 Permutation A057506 applied four times ("^4"), permutation A071662 squared.
%H A071666 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 A071666 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%Y A071666 Inverse permutation: A071665 and also its car/cdr-flipped conjugate, i.e. A071666(n) = A057163(A071665(A057163(n))) = A057506(A071664(n)) = A071662(A071662(n)). Cf. also A071662, A071668, A071670.
%K A071666 nonn
%O A071666 0,3
%A A071666 _Antti Karttunen_, May 30 2002