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 A252002 #11 Mar 22 2022 00:11:22 %S A252002 1,3,5,7,9,8,6,4,2,90,18,16,14,12,10,11,13,15,17,79,20,22,24,26,28,27, %T A252002 25,23,19,68,39,35,33,31,29,30,32,34,21,43,41,37,45,47,49,48,46,36,38, %U A252002 51,52,53,54,55,50,56,57,58,40,42,44,59,60,61,62,63,64 %N A252002 Inverse permutation to A252001. %H A252002 Reinhard Zumkeller, <a href="/A252002/b252002.txt">Table of n, a(n) for n = 1..9999</a> %H A252002 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %o A252002 (Haskell) %o A252002 import Data.List (elemIndex); import Data.Maybe (fromJust) %o A252002 a252002 = (+ 1) . fromJust . (`elemIndex` a252001_list) %Y A252002 Cf. A252001 (inverse), A252078 (fixed points). %K A252002 nonn %O A252002 1,2 %A A252002 _Reinhard Zumkeller_, Dec 12 2014