

A036552


List of pairs (m,2m) where m is the least unused positive number.


6



1, 2, 3, 6, 4, 8, 5, 10, 7, 14, 9, 18, 11, 22, 12, 24, 13, 26, 15, 30, 16, 32, 17, 34, 19, 38, 20, 40, 21, 42, 23, 46, 25, 50, 27, 54, 28, 56, 29, 58, 31, 62, 33, 66, 35, 70, 36, 72, 37, 74, 39, 78, 41, 82, 43, 86, 44, 88, 45, 90, 47, 94, 48, 96, 49, 98, 51, 102
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OFFSET

1,2


COMMENTS

A permutation of the natural numbers. Inverse permutation is A065037.


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
P. Erdős, R. Freud, and N. Hegyvári, Arithmetical properties of permutations of integers, Acta Mathematica Hungarica 41:12 (1983), pp 169176.
Index entries for sequences that are permutations of the natural numbers


MATHEMATICA

w = {}; Do[ w = If[ FreeQ[w, k], w = Join[w, {k, 2k}], w], {k, 100}]; w
(* JeanFrançois Alcover, Nov 04 2011, after Wouter Meeussen *)


PROG

(Haskell)
import Data.List (delete)
a036552 n = a036552_list !! (n1)
a036552_list = g [1..] where
g (x:xs) = x : (2*x) : (g $ delete (2*x) xs)
 Reinhard Zumkeller, Feb 07 2011


CROSSREFS

Alternating merge of A003159 and A036554. Cf. A064736, A065037.
Sequence in context: A082332 A154285 A258078 * A257987 A132169 A273666
Adjacent sequences: A036549 A036550 A036551 * A036553 A036554 A036555


KEYWORD

nonn,easy,nice


AUTHOR

Tom Verhoeff


STATUS

approved



