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 A112977 #6 Mar 30 2012 18:50:53 %S A112977 1,2,3,8,6,10,12,14,5,18,20,4,21,22,25,26,9,27,30,32,33,11,34,36,39, %T A112977 13,15,40,42,44,46,48,16,49,51,52,54,55,57,19,58,60,7,62,64,65,66,68, %U A112977 24,69,70,74,75,76,77,78,81,82,28,84,86,29,88,90,91,92,31,94,95,98,99,100,102 %N A112977 A112975(A112975(n)). %C A112977 Inverse integer permutation of A112979; %C A112977 A112978(a(n)) = a(A112978(n)) = A112975(n). %H A112977 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %K A112977 nonn %O A112977 1,2 %A A112977 _Reinhard Zumkeller_, Oct 08 2005