A064745 Inverse permutation to A064736.

1, 2, 4, 6, 8, 3, 10, 12, 14, 16, 18, 5, 20, 22, 24, 26, 28, 30, 32, 7, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 9, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 11, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124

Offset: 1

Author

N. J. A. Sloane, Oct 21 2001

Keywords

• nonn
• easy

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• Index entries for sequences that are permutations of the natural numbers

Programs

Haskell

import Data.List (elemIndex)
import Data.Maybe (fromJust)
a064745 n = fromJust (elemIndex n a064736_list) + 1
-- Reinhard Zumkeller, Mar 23 2012

Mathematica

max = 124; ClearAll[a, b]; A064736 = {a[1]=1, a[2]=2}; a[n_] := a[n] = (an = If[OddQ[n], a[n-1]*a[n+1], First[ Complement[ Range[n], A064736]]]; AppendTo[A064736, an]; an); Do[b[a[n]] = n, {n, 1, max}]; A064745 = Table[b[n], {n, 1, a[max]}] (* Jean-François Alcover, Aug 07 2012 *)

Extensions

More terms from Vladeta Jovovic, Oct 21 2001