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A215258 Smallest number h such that (2n+1)*h is a repunit (A002275), or 0 if no such h exists. 1
1, 37, 0, 15873, 12345679, 1, 8547, 0, 65359477124183, 5847953216374269, 5291, 48309178743961352657, 0, 4115226337448559670781893, 38314176245210727969348659, 3584229390681, 3367, 0, 3, 2849, 271, 2583979328165374677, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

T. D. Noe, Table of n, a(n) for n = 0..200

MATHEMATICA

Table[If[GCD[n, 10] > 1, 0, k = MultiplicativeOrder[10, 9*n]; (10^k - 1)/(9*n)], {n, 1, 51, 2}] (* T. D. Noe, Sep 11 2012 *)

CROSSREFS

A bisection of A190301.

Sequence in context: A180463 A190301 A077575 * A176795 A272725 A057639

Adjacent sequences:  A215255 A215256 A215257 * A215259 A215260 A215261

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Sep 11 2012

STATUS

approved

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Last modified February 18 09:39 EST 2020. Contains 332011 sequences. (Running on oeis4.)