A216416 a(n) = smallest m such that 2n-1 | 10^m+1, or 0 if no such m exists.

1, 0, 0, 3, 0, 1, 3, 0, 8, 9, 0, 11, 0, 0, 14, 0, 0, 0, 0, 0, 0, 0, 0, 23, 21, 0, 0, 0, 0, 29, 30, 0, 0, 0, 0, 0, 4, 0, 3, 0, 0, 0, 0, 0, 22, 3, 0, 0, 48, 0, 2, 17, 0, 0, 54, 0, 56, 0, 0, 0, 11, 0, 0, 21, 0, 65, 9, 0, 4, 23, 0, 3, 0, 0, 74, 0, 0, 0, 39, 0, 33, 0

Offset

1,4

Links

V. Raman, Table of n, a(n) for n = 1..99.

Prog

(PARI) for(i=0, 200, i++; m=0; for(x=1, i, if(((10^x+1))%i==0, m=x; break)); print1(m", ")) \\ V. Raman, Nov 22 2012

Crossrefs

Cf. A002326.

Sequence in context: A137297 A178117 A095710 * A291960 A160052 A035650

Adjacent sequences: A216413 A216414 A216415 * A216417 A216418 A216419

Keyword

nonn

Author

V. Raman, Sep 07 2012

Status

approved