A216470 a(n) = smallest m such that 2n-1 | (10^m+1)/11, or 0 if no such m exists.

1, 0, 0, 3, 0, 11, 3, 0, 0, 9, 0, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 23, 21, 0, 0, 0, 0, 29, 0, 0, 0, 0, 0, 0, 0, 0, 33, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 17, 0, 0, 0, 0, 0, 0, 0, 0, 121, 0, 0, 21, 0, 65, 9, 0, 0, 23, 0, 33, 0, 0, 0, 0, 0, 0, 39, 0, 33, 0, 0, 83, 39, 0, 0, 0, 0, 89, 0, 0, 0, 0, 0, 0, 0, 0, 49, 0

Offset

1,4

Links

Table of n, a(n) for n=1..100.

Prog

(PARI) for(i=0, 200, i++; m=0; for(x=0, i, x++; if(((10^x+1)/11)%i==0, m=x; break)); print1(m", ")) \\ V. Raman, Nov 22 2012

Crossrefs

Cf. A002326.

Sequence in context: A094897 A252096 A346240 * A182259 A211802 A249775

Adjacent sequences: A216467 A216468 A216469 * A216471 A216472 A216473

Keyword

nonn

Author

V. Raman, Sep 07 2012

Status

approved