A329792 Smallest positive k such that k*n contains only the digits 1,2,3,4,5, or -1 if no such k exists.
-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
Offset: 0
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
Programs
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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
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