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A360073
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a(n) is the greatest divisor of n divisible by the product of its own digits.
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2
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1, 2, 3, 4, 5, 6, 7, 8, 9, 5, 11, 12, 1, 7, 15, 8, 1, 9, 1, 5, 7, 11, 1, 24, 5, 2, 9, 7, 1, 15, 1, 8, 11, 2, 7, 36, 1, 2, 3, 8, 1, 7, 1, 11, 15, 2, 1, 24, 7, 5, 3, 4, 1, 9, 11, 8, 3, 2, 1, 15, 1, 2, 9, 8, 5, 11, 1, 4, 3, 7, 1, 36, 1, 2, 15, 4, 11, 6, 1, 8, 9
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OFFSET
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1,2
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COMMENTS
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Numbers divisible by the product of their digits are called Zuckerman numbers (A007602).
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LINKS
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FORMULA
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EXAMPLE
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For n = 10:
- the divisors of 10 are 1, 2, 5 and 10,
- 5 is divisible by 5 whereas 10 is not divisible by 1*0,
- so a(10) = 5.
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PROG
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(PARI) a(n) = { fordiv (n, d, my (t=n/d, p=vecprod(digits(t))); if (p && t%p==0, return (t))) }
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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