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 A162502 #7 Mar 18 2022 21:52:25 %S A162502 1,5,9,13,17,21,25,29,33,2,3,4,8,12,16,20,24,28,32,6,7,39,40,42,44,46, %T A162502 48,50,52,10,11,41,57,58,60,62,64,66,68,14,15,43,59,73,74,76,78,80,82, %U A162502 18,19,45,61,75,87,88,90,92,94,22,23,47,63,77,89,99,100,102,104,26,27 %N A162502 Inverse permutation to A162501. %C A162502 A162501(a(n)) = a(A162501(n)) = n. %C A162502 a(a(n)) = A162504(n). %H A162502 R. Zumkeller, <a href="/A162502/b162502.txt">Table of n, a(n) for n = 1..1000</a> %H A162502 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %K A162502 nonn %O A162502 1,2 %A A162502 _Reinhard Zumkeller_, Jul 05 2009