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 A268531 #9 Feb 17 2016 15:04:38
%S A268531 1,3,2,10,7,4,17,9,6,27,19,11,24,16,8,86,21,5,65,26,18,57,31,88,62,23,
%T A268531 15,80,54,28,98,85,20,46,33,12,77,64,25,38,95,82,69,56,30,113,100,87,
%U A268531 74,61,22,118,35,14,149,79,66,53,123,40,110,97,84,273,71,58,128,45,32,203,102,89,146,76,63
%N A268531 Position of n in A268642 (or, inverse permutation to A268642).
%C A268531 Apparently there is a claim that A268642 contains every positive integer exactly once, so this sequence is well-defined.
%H A268531 N. J. A. Sloane, <a href="/A268531/b268531.txt">Table of n, a(n) for n = 1..945</a>
%p A268531 # Let b1 be a list of the initial terms of A268642
%p A268531 ans:=[];
%p A268531 for n from 1 to nops(b1) do
%p A268531 if member(n,b1,'p') then ans:=[op(ans),p];
%p A268531 else lprint("missed", n); break; fi;
%p A268531 od;
%p A268531 ans;
%Y A268531 Cf. A268642.
%K A268531 nonn
%O A268531 1,2
%A A268531 _N. J. A. Sloane_, Feb 17 2016