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A115300
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Greatest digit of n * least digit of n.
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5
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1, 4, 9, 16, 25, 36, 49, 64, 81, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 0, 6, 12, 18, 24, 30, 36, 42, 48, 54, 0, 7, 14, 21, 28, 35, 42, 49, 56, 63, 0, 8
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OFFSET
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1,2
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COMMENTS
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a(101) = 0 and A111707(101) = 1, but all previous terms match.
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LINKS
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FORMULA
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EXAMPLE
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a(3) = 3 * 3 = 9, a(232) = 3 * 2 = 6, a(1889009898) = 9 * 0 = 0.
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MATHEMATICA
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Array[Max[#] * Min[#] &@ IntegerDigits[#] &, 81] (* James C. McMahon, Aug 18 2024 *)
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PROG
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(Haskell)
(Python)
def a(n): d = list(map(int, str(n))); return max(d) * min(d)
(PARI) a(n) = my(d=digits(n)); vecmin(d)*vecmax(d); \\ Michel Marcus, Aug 18 2024
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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