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A135366 a(n) is the smallest nonnegative k such that n divides 2^k+k. 2
0, 2, 1, 4, 4, 2, 6, 8, 7, 4, 3, 8, 12, 6, 7, 16, 16, 14, 18, 4, 19, 8, 22, 8, 33, 12, 7, 40, 11, 26, 23, 32, 8, 16, 6, 32, 5, 18, 37, 24, 40, 38, 42, 8, 7, 22, 10, 32, 61, 84, 38, 12, 35, 32, 46, 40, 32, 28, 24, 44 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(2^m)=2^m for m>0. If p is prime then by Fermat, a(p)<=p-1. 25 is the smallest n with a(n)>n.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

a(9)=7 since 2^7+7= 9*15 and 2^k+k is not divisible by 9 for 0<=k<7.

MATHEMATICA

sk[n_]:=Module[{k=0}, While[!Divisible[2^k+k, n], k++]; k]; Array[sk, 60] (* Harvey P. Dale, Jun 01 2013 *)

CROSSREFS

Sequence in context: A261070 A249140 A113421 * A247248 A192017 A180566

Adjacent sequences:  A135363 A135364 A135365 * A135367 A135368 A135369

KEYWORD

nonn

AUTHOR

John L. Drost, Feb 16 2008

EXTENSIONS

Corrected by Harvey P. Dale, Jun 01 2013

STATUS

approved

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Last modified May 20 20:16 EDT 2019. Contains 323426 sequences. (Running on oeis4.)