A216812 - OEIS

A216812

Smallest positive number divisible by n whose decimal expansion has the form 22...200...0.

2, 2, 222, 20, 20, 222, 222222, 200, 222222222, 20, 2222222222, 2220, 222222222222, 222222, 2220, 2000, 2222222222222222, 222222222, 222222222222222222, 20, 222222

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..21.

FORMULA

If n=3^k, a(n)=2(10^n-1)/9. For all n, a(n) <= 2(10^n-1)/9.

a(2^k)= 2*10^(k-1).

If p=prime, a(p) = 2(10^(p-1)-1)/9.

CROSSREFS

Cf. A078241, A216481.

Sequence in context: A304915 A216481 A078241 * A068103 A335257 A119512

Adjacent sequences: A216809 A216810 A216811 * A216813 A216814 A216815

KEYWORD

nonn,base

AUTHOR

N. J. A. Sloane, Sep 18 2012

STATUS

approved