A215258 Smallest number h such that (2n+1)*h is a repunit (A002275), or 0 if no such h exists.

1, 37, 0, 15873, 12345679, 1, 8547, 0, 65359477124183, 5847953216374269, 5291, 48309178743961352657, 0, 4115226337448559670781893, 38314176245210727969348659, 3584229390681, 3367, 0, 3, 2849, 271, 2583979328165374677, 0

Offset: 0

Author

N. J. A. Sloane, Sep 11 2012

Keywords

• nonn

Links

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

Crossrefs

A bisection of A190301.

Programs

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 *)