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A329792 Smallest positive k such that k*n contains only the digits 1,2,3,4,5, or -1 if no such k exists. 2
-1, 1, 1, 1, 1, 1, 2, 2, 3, 5, -1, 1, 1, 1, 1, 1, 2, 2, 3, 6, -1, 1, 1, 1, 1, 1, 2, 2, 4, 5, -1, 1, 1, 1, 1, 1, 4, 3, 3, 6, -1, 1, 1, 1, 1, 1, 7, 3, 3, 5, -1, 1, 1, 1, 1, 1, 2, 2, 4, 6, -1, 2, 2, 4, 8, 5, 2, 2, 8, 5, -1, 2, 2, 7, 3, 3, 2, 2, 3, 7, -1, 3, 16, 4, 3, 3, 4, 5, 4, 5, -1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,7

COMMENTS

a(n) > 0 iff n is not a multiple of 10.

REFERENCES

G. Galperin  and Y. J. Ionin (Proposers), and M. Reid (Solver), Problem 12034, Amer. Math. Monthly, 126:10, 950-951, Dec. 2019.

LINKS

Rémy Sigrist, Table of n, a(n) for n = 0..25000

PROG

(Python)

def A329792(n):

    if n % 10:

        m, s = 1, set('12345')

        while not set(str(m*n)) <= s:

            m += 1

        return m

    else:

        return -1 # Chai Wah Wu, Dec 04 2019

CROSSREFS

Cf. A084545, A329793.

Sequence in context: A093927 A067088 A065519 * A058256 A140183 A280408

Adjacent sequences:  A329789 A329790 A329791 * A329793 A329794 A329795

KEYWORD

sign,look,base

AUTHOR

N. J. A. Sloane, Dec 03 2019

STATUS

approved

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Last modified January 23 10:50 EST 2020. Contains 331171 sequences. (Running on oeis4.)