A120008 Smallest k such that the concatenation from 1 to k and back to 1 is divisible by 2n-1, or 0 if no such k exists.

1, 3, 0, 6, 3, 2, 6, 0, 109, 103, 6, 100001, 0, 9, 1006, 17, 6, 0, 3, 6, 5, 103, 0, 1000002, 6, 129, 100012, 0

Offset: 1

Author

Franklin T. Adams-Watters, Jun 02 2006

Keywords

• base
• nonn

Comments

a(29), 2n-1 = 57, is at least 1e8.

Crossrefs

Cf. A077189.