A084933 Inverse of A084937.

1, 2, 3, 5, 4, 11, 6, 8, 7, 14, 9, 26, 10, 20, 18, 17, 12, 29, 13, 32, 15, 23, 16, 56, 21, 35, 22, 38, 19, 59, 24, 41, 33, 47, 25, 62, 27, 44, 39, 53, 28, 95, 30, 50, 36, 65, 31, 92, 34, 74, 42, 68, 37, 98, 40, 71, 49, 77, 43, 101, 45, 80, 46, 83, 48, 137, 51, 86, 52

Offset: 1

Author

Reinhard Zumkeller, Jun 13 2003

Keywords

• nonn

Comments

Empirically, A084937 is a permutation of the natural numbers. Assuming that is true, we will have a(A084937(n)) = A084937(a(n)) = n. (Comment revised by N. J. A. Sloane, Nov 05 2014)

Links

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

Crossrefs

Cf. A084937. For records see A249684, A249685.

Programs

Haskell

import Data.List (elemIndex)
import Data.Maybe (fromJust)
a084933 n = (fromJust $ elemIndex n a084937_list) + 1
-- Reinhard Zumkeller, Jan 28 2012

Mathematica

f[s_] := Block[{k = 1, l = Take[s, -2]}, While[ Union[ GCD[k, l]] != {1} || MemberQ[s, k], k++]; Append[s, k]]; Ordering@ Nest[f, {1, 2}, 100] (* Robert G. Wilson v, Jun 26 2011 *)