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 A117923 #6 Mar 30 2012 18:50:54 %S A117923 1,2,3,4,5,6,7,8,9,10,15,12,17,14,11,16,13,18,19,20,21,22,23,24,25,34, %T A117923 27,28,29,38,31,30,33,40,35,26,43,36,41,32,39,42,37,44,53,54,49,48,55, %U A117923 50,45,46,51,52,47,56,57,72,65,64,73,62,59,70,71,58,69,68,61,60,63,66 %N A117923 A055265(A055265(n)). %C A117923 a(n) = A117924(n) for n<= 25; %C A117923 Permutation of the natural numbers, inverse: A117924; %C A117923 fixed points: A117925. %H A117923 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %K A117923 nonn %O A117923 1,2 %A A117923 _Reinhard Zumkeller_, Apr 03 2006