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A084933
Inverse of A084937.
4
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
1,2
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)
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 *)
PROG
(Haskell)
import Data.List (elemIndex)
import Data.Maybe (fromJust)
a084933 n = (fromJust $ elemIndex n a084937_list) + 1
-- Reinhard Zumkeller, Jan 28 2012
CROSSREFS
Cf. A084937. For records see A249684, A249685.
Sequence in context: A325549 A370895 A112060 * A355065 A213900 A213648
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jun 13 2003
STATUS
approved