A356758 a(n) is the number of nonzero digits in n!.

1, 1, 1, 1, 2, 2, 2, 2, 3, 5, 5, 6, 5, 6, 9, 9, 10, 11, 11, 12, 12, 13, 14, 18, 18, 17, 19, 20, 20, 24, 24, 27, 26, 29, 28, 32, 32, 32, 29, 35, 39, 35, 39, 40, 43, 44, 42, 49, 48, 49, 46, 49, 50, 53, 54, 56, 58, 57, 62, 62, 63, 58, 66, 67, 70, 71, 70, 73, 72, 78, 81

Offset

0,5

Links

Table of n, a(n) for n=0..70.

Index entries for sequences related to factorial numbers

Formula

a(n) = A034886(n!) - A027869(n!).

Mathematica

Table[Length[Select[IntegerDigits[n!], Positive]], {n, 0, 70}]

Prog

(PARI) a(n) = #select(x->(x>0), digits(n!)); \\ Michel Marcus, Aug 26 2022
(Python)
from math import factorial
def a(n): return len(str(factorial(n)).replace("0", ""))
print([a(n) for n in range(71)]) # Michael S. Branicky, Aug 26 2022

Crossrefs

Cf. A000142, A027869, A034886, A356757.

Sequence in context: A316899 A352828 A029100 * A098133 A138185 A225941

Adjacent sequences: A356755 A356756 A356757 * A356759 A356760 A356761

Keyword

nonn,base

Author

Stefano Spezia, Aug 26 2022

Status

approved