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 A071661 #5 Apr 30 2014 01:53:48
%S A071661 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 A071661 28,51,44,53,30,25,39,56,47,33,60,45,54,57,48,61,31,34,26,24,38,40,43,
%U A071661 29,52,58,62,49,46,55,35,32,27,41,63,59,50,36,64,65,107,121,79,149,126
%N A071661 Permutation A057505 applied twice ("squared").
%H A071661 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 A071661 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%Y A071661 Inverse permutation: A071662 and also its car/cdr-flipped conjugate, i.e. A071661(n) = A057163(A071662(A057163(n))) = A057505(A057505(n)). Cf. also A071663, A071665, A071667, A071669.
%K A071661 nonn
%O A071661 0,3
%A A071661 _Antti Karttunen_, May 30 2002