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Inverse permutation of the sequence of positive integers at A232642.
2

%I #10 Jan 15 2018 23:39:09

%S 1,2,4,3,6,5,9,8,14,7,12,11,19,10,17,16,27,15,25,24,40,13,22,21,35,20,

%T 33,32,53,18,30,29,48,28,46,45,74,26,43,42,69,41,67,66,108,23,38,37,

%U 61,36,59,58,95,34,56,55,90,54,88,87,142,31,51,50,82,49

%N Inverse permutation of the sequence of positive integers at A232642.

%H Clark Kimberling and Reinhard Zumkeller, <a href="/A232643/b232643.txt">Table of n, a(n) for n = 1..10000</a> (first 1000 terms from Clark Kimberling)

%t z = 14; g[1] = {1}; g[2] = {2}; g[n_] := Riffle[g[n - 1] + 1, 2 g[n - 1] + 2]; j[2] = Join[g[1], g[2]]; j[n_] := Join[j[n - 1], g[n]]; g1[n_] := DeleteDuplicates[DeleteCases[g[n], Alternatives @@ j[n - 1]]]; g1[1] = g[1]; g1[2] = g[2]; t = Flatten[Table[g1[n], {n, 1, z}]] (* A232642 *)

%t Table[Length[g1[n]], {n, 1, z}] (* A000045 *)

%t Flatten[Table[Position[t, n], {n, 1, 200}]] (* A232643 *)

%o (Haskell)

%o import Data.List (elemIndex); import Data.Maybe (fromJust)

%o a232643 = (+ 1) . fromJust . (`elemIndex` a232642_list)

%o -- _Reinhard Zumkeller_, May 14 2015

%Y Cf. A232559, A232639, A232642, A000045.

%K nonn,easy

%O 1,2

%A _Clark Kimberling_, Nov 28 2013

%E b-File corrected by _Reinhard Zumkeller_, May 14 2015