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 A160516 #15 Feb 14 2018 18:29:24 %S A160516 1,2,5,3,6,4,17,8,10,7,18,9,23,20,11,13,24,15,58,12,16,19,59,14,33,22, %T A160516 28,21,62,26,63,31,29,25,34,36,66,57,39,32,67,35,72,30,27,60,125,37, %U A160516 49,44,40,38,126,47,45,42,71,61,131,56,134,64,48,52,80,46,135,41,76,43 %N A160516 Inverse permutation to A075075. %C A160516 This is a permutation of the positive integers (provided A075075 really is a permutation). %H A160516 H. v. Eitzen, <a href="/A160516/b160516.txt">Table of n, a(n) for n = 1..50000</a> %F A160516 A075075(a(n)) = n. %e A160516 A075075(7) = 10, therefore a(10) = 7. %e A160516 A075055(17) = 7, therefore a(7) = 17. %t A160516 f[s_List] := Block[{m = Numerator[s[[ -1]]/s[[ -2]]]}, k = m; While[MemberQ[s, k], k += m]; Append[s, k]]; s = Nest[f, {1, 2}, 200]; Table[ Position[s, n, 1, 1], {n, 70}] // Flatten (* _Robert G. Wilson v_, May 20 2009 *) %o A160516 (Haskell) %o A160516 import Data.List (elemIndex) %o A160516 import Data.Maybe (fromJust) %o A160516 a160516 = (+ 1) . fromJust . (`elemIndex` a075075_list) %o A160516 -- _Reinhard Zumkeller_, Dec 19 2012 %Y A160516 Cf. A185635 (fixed points). %K A160516 nonn %O A160516 1,2 %A A160516 _Hagen von Eitzen_, May 16 2009