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 A249918 #16 Mar 26 2022 14:32:17 %S A249918 1,4,7,12,11,8,3,2,9,14,13,6,5,22,15,10,17,16,21,26,23,18,19,24,25,20, %T A249918 29,28,27,30,33,32,31,34,35,40,37,38,39,36,41,44,43,42,45,46,47,48,57, %U A249918 58,49,54,53,50,59,56,51,52,55,60,61,62,63,68,67,64,65 %N A249918 Inverse permutation to A203069. %H A249918 Reinhard Zumkeller, <a href="/A249918/b249918.txt">Table of n, a(n) for n = 1..10000</a> %H A249918 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %o A249918 (Haskell) %o A249918 import Data.List (elemIndex); import Data.Maybe (fromJust) %o A249918 a249918 = (+ 1) . fromJust . (`elemIndex` a203069_list) %Y A249918 Cf. A203069, A249920. %K A249918 nonn %O A249918 1,2 %A A249918 _Reinhard Zumkeller_, Jan 14 2015