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URL: https://oeis.org/A300659

⇱ A300659 - OEIS


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A300659
Product of digits of n!.
0
1, 1, 2, 6, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
OFFSET
0,3
COMMENTS
Also multiplicative digital root of n!.
Decimal expansion of 2817/25000. - Eric Chen, Jun 06 2018
FORMULA
G.f.: 1 + x + 2*x^2 + 6*x^3 + 8*x^4.
a(n) = 0 for n >= 5.
a(n) = A031347(A000142(n)).
a(n) = A007954(A000142(n)). - Eric Chen, Jun 06 2018
MATHEMATICA
Array[Times @@ IntegerDigits[#!] &, 105] (* Michael De Vlieger, Jun 06 2018 *)
PROG
(Magma) [&*Intseq(Factorial(n)): n in [0..100]];
(PARI) a(n) = my(d=digits(n!)); prod(k=1, #d, d[k]); \\ Michel Marcus, Jun 05 2018
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Jaroslav Krizek, Jun 05 2018
STATUS
approved