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 A118764 #10 Sep 22 2016 20:50:08
%S A118764 0,1,2,3,4,5,6,7,8,9,11,12,13,14,15,16,17,18,19,10,21,22,23,24,25,26,
%T A118764 27,28,20,29,31,32,33,34,35,36,37,38,39,30,41,42,43,44,45,46,47,48,40,
%U A118764 49,51,52,53,54,55,56,57,58,59,50,61,62,63,64,65,66,67,68,60,69,71,72,73
%N A118764 Inverse of A118763.
%C A118764 Permutation of the natural numbers with fixed points A118767: a(A118767(n))=A118767(n);
%C A118764 A118766(n) = a(a(n)).
%H A118764 Robert G. Wilson v, <a href="/A118764/b118764.txt">Table of n, a(n) for n = 0..10000</a>
%H A118764 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%t A118764 (* first do Mmca in A118763, then *) Flatten@ Table[Position[s, n], {n, 0, 100}] - 1 (* _Robert G. Wilson v_, Sep 22 2016 *)
%Y A118764 Cf. A118758.
%K A118764 nonn
%O A118764 0,3
%A A118764 _Reinhard Zumkeller_, May 01 2006