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 A281117 #6 Jan 15 2017 12:06:51 %S A281117 1,2,4,3,6,5,8,10,11,7,13,12,15,9,17,19,20,18,22,24,25,14,27,26,29,16, %T A281117 31,32,34,30,36,33,38,21,40,39,42,23,44,41,46,45,48,50,51,28,53,52,55, %U A281117 57,58,60,61,59,63,56,65,35,66,64,68,37,70,72,73,71,75 %N A281117 Inverse permutation to A280985. %C A281117 a(A280985(n))=A280985(a(n))=n for any n>0. %H A281117 Rémy Sigrist, <a href="/A281117/b281117.txt">Table of n, a(n) for n = 1..10000</a> %Y A281117 Cf. A280985. %K A281117 nonn %O A281117 1,2 %A A281117 _Rémy Sigrist_, Jan 15 2017