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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, 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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

CROSSREFS

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

Sequence in context: A003110 A100956 A304915 * A078241 A216812 A068103

Adjacent sequences:  A216478 A216479 A216480 * A216482 A216483 A216484

KEYWORD

sign,base

AUTHOR

V. Raman, Sep 07 2012

STATUS

approved

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Last modified December 14 01:22 EST 2019. Contains 329978 sequences. (Running on oeis4.)