OFFSET
0,5
LINKS
T. D. Noe, Table of n, a(n) for n = 0..1000
FORMULA
EXAMPLE
a(4) = 3 because 4! = 24_10 = 11000_2 and it has 3 zero digits.
MATHEMATICA
Table[Count[IntegerDigits[n!, 2], 0], {n, 0, 100}] (* T. D. Noe, Apr 10 2012 *)
DigitCount[Range[0, 70]!, 2, 0] (* Harvey P. Dale, Mar 11 2019 *)
PROG
(PARI) for(n=1, 300, b=binary(n!); print1(sum(k=1, length(b), if(b[k], 0, 1))", "))
(Python)
import math
def a(n):
return bin(math.factorial(n))[2:].count("0")
# Indranil Ghosh, Dec 23 2016
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jose R. Brox (tautocrona(AT)terra.es), Jan 26 2003
STATUS
approved