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 A072799 #5 May 01 2014 02:47:43 %S A072799 1,2,4,3,5,9,10,8,6,7,13,12,11,14,23,24,27,26,28,22,25,20,15,16,21,18, %T A072799 17,19,36,37,35,32,33,34,31,29,30,41,40,39,38,42,65,66,69,68,70,78,79, %U A072799 77,74,75,83,82,81,84,64,67,76,73,80,62,71,57,43,44,58,46,45,47,63,72 %N A072799 Self-inverse permutation of natural numbers: A072798(n-1)+1. (one-based). %H A072799 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %K A072799 nonn %O A072799 1,2 %A A072799 _Antti Karttunen_, Jun 12 2002