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A371281
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Last digit of the product of decimal digits of n.
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2
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 2, 4, 6, 8, 0, 2, 4, 6, 8, 0, 3, 6, 9, 2, 5, 8, 1, 4, 7, 0, 4, 8, 2, 6, 0, 4, 8, 2, 6, 0, 5, 0, 5, 0, 5, 0, 5, 0, 5, 0, 6, 2, 8, 4, 0, 6, 2, 8, 4, 0, 7, 4, 1, 8, 5, 2, 9, 6, 3, 0, 8, 6, 4, 2, 0, 8, 6, 4, 2, 0, 9, 8
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OFFSET
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0,3
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COMMENTS
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n=0 is taken as one 0 digit so that its product of digits is A007954(0) = 0.
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LINKS
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FORMULA
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EXAMPLE
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n = 15: a(15) = 1*5 mod 10 = 5.
n = 26: a(26) = 2*6 mod 10 = 2.
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MAPLE
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a:= n-> `if`(n<10, n, irem(n, 10, 'q')*a(q) mod 10):
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MATHEMATICA
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a[n_] := Mod[Times @@ IntegerDigits[n], 10]; Array[a, 100, 0] (* Amiram Eldar, Mar 17 2024 *)
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PROG
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(Python)
from math import prod
def a(n): return prod(map(int, str(n)))%10
(PARI) a(n) = if (n==0, 0, vecprod(digits(n)) % 10); \\ Michel Marcus, Mar 17 2024
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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