A216481 a(n) is the least multiple of n which uses only digit 2, or a(n) = -1 if no such multiple exists.

2, 2, 222, -1, -1, 222, 222222, -1, 222222222, -1, 22, -1, 222222, 222222, -1, -1, 2222222222222222, 222222222, 222222222222222222, -1, 222222, 22, 2222222222222222222222, -1, -1, 222222, 222222222222222222222222222, -1, 2222222222222222222222222222, -1, 222222222222222, -1, 222222, 2222222222222222, -1, -1, 222, 222222222222222222, 222222, -1, 22222, 222222

Offset

1,1

Links

Table of n, a(n) for n=1..42.

Crossrefs

Cf. A004290, A078241, A079339, A181060, A181061, A216812.

Sequence in context: A100956 A358621 A304915 * A078241 A216812 A068103

Adjacent sequences: A216478 A216479 A216480 * A216482 A216483 A216484

Keyword

sign,base

Author

V. Raman, Sep 07 2012

Status

approved