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 A163240 #7 Mar 18 2022 21:53:03 %S A163240 0,2,4,1,9,5,8,13,24,17,12,18,6,11,7,3,35,27,34,43,14,20,26,19,32,41, %T A163240 33,25,62,51,42,52,112,97,84,98,70,83,71,59,40,50,60,49,73,61,72,85, %U A163240 28,37,29,21,58,47,38,48,31,23,30,39,10,16,22,15,135,119,134,151,90 %N A163240 Inverse permutation to A163239. %H A163240 A. Karttunen, <a href="/A163240/b163240.txt">Table of n, a(n) for n = 0..4095</a> %H A163240 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %Y A163240 Inverse: A163239. a(n) = A163236(A163241(n)). Cf. A163238. %K A163240 nonn %O A163240 0,2 %A A163240 _Antti Karttunen_, Jul 29 2009