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A138255 Smallest positive integer m such that n divides [2^m/m] (=A000799(m)). 9
1, 1, 5, 4, 6, 5, 9, 8, 7, 6, 12, 15, 14, 9, 13, 8, 10, 7, 21, 28, 13, 24, 48, 15, 22, 14, 19, 9, 30, 13, 11, 8, 31, 10, 13, 21, 38, 21, 14, 39, 22, 13, 29, 63, 13, 67, 135, 65, 43, 22, 10, 15, 35, 19, 24, 9, 21, 30, 120, 28, 62, 11, 13, 16, 14, 31, 69, 20, 67, 13, 145, 21, 19, 38 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

This sequence is well-defined.

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

Romanian Master in Mathematics Contest, Bucharest, 2007, Problem 3

MAPLE

f:= proc(n) local m;

     for m from 1 do if floor(2^m/m) mod n = 0 then return m fi od

end proc:

map(f, [$1..100]); # Robert Israel, Jun 07 2018

MATHEMATICA

a[n_] := For[m = 1, True, m++, If[Divisible[Floor[2^m/m], n], Return[m]]];

Array[a, 100] (* Jean-François Alcover, Mar 22 2019 *)

CROSSREFS

Cf. A000799, A138256, A138257, A138258, A138259, A138260, A138261, A138262, A138263.

Sequence in context: A298513 A021187 A075194 * A153451 A190143 A089687

Adjacent sequences:  A138252 A138253 A138254 * A138256 A138257 A138258

KEYWORD

nonn

AUTHOR

Max Alekseyev, Mar 09 2008

STATUS

approved

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Last modified September 20 03:55 EDT 2019. Contains 327212 sequences. (Running on oeis4.)