OFFSET
0,11
FORMULA
EXAMPLE
a(10)=2 since 10! = 3628800 = 16^2 * 14175.
PROG
(Python 3.10+)
def A090621(n): return (n-n.bit_count())>>2 # Chai Wah Wu, Jul 09 2022
(PARI) a(n) = valuation(n!, 16); \\ Michel Marcus, Jul 10 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Henry Bottomley, Dec 06 2003
STATUS
approved