When expressed in base 8, N! terminates in a block of exactly 21 zeros. Find the largest positive integer N with this property. (Express N as a decimal number.)
(I got 159, but this is wrong.)
N = 66 in base 10. If you convert it to base 8 =102 and 102! ends in 21 zeros.
Wouldn't it be the smallest positive integer N that you are looking for?
67, wrote python to do it. Also u in my aops class right? who r u? cheater
def TrailingZeros(n): count = 0
i=2 while (n/i>=1): count += int(n/i) i *= 2
return int(count)
n = 66
print(TrailingZeros(n)//3)
