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A122182 Least positive number k such that 2^k mod k = 2n, or 0 if no such k exists. 2
1, 3, 6, 10669, 9, 18, 3763, 1010, 20, 35, 2951, 42, 50, 27, 36, 49, 56, 110, 697, 578, 156, 540923, 70, 287, 104, 147, 4044, 970, 220, 59378, 119, 345, 66, 3007, 75, 1990362, 184, 190, 100, 115, 81, 162, 470, 406, 812, 6631, 105, 310, 160, 207, 322 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..50.

MATHEMATICA

lpn[n_]:=Module[{k=1}, While[PowerMod[2, k, k]!=2n, k++]; k]; Array[lpn, 60, 0] (* Harvey P. Dale, Jul 23 2012 *)

CROSSREFS

A bisection of A036236: a(n) = A036236(2n).

Cf. A124977.

Sequence in context: A157548 A134901 A157564 * A276701 A157596 A111316

Adjacent sequences:  A122179 A122180 A122181 * A122183 A122184 A122185

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, May 11 2007, Jul 18 2008

EXTENSIONS

New definition from Benoit Jubin, Jul 17 2008

More terms from Max Alekseyev, May 08 2009

STATUS

approved

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Last modified April 25 23:48 EDT 2019. Contains 322465 sequences. (Running on oeis4.)