def is_powerful(n):
"""if a prime p divides n then p^2 must also divide n
(also called squareful, square full, square-full or 2-full numbers).
"""
for f in itertools2.unique(math2.prime_factors(n)):
if n%(f*f): return False
return True
def is_powerful(n):
"""if a prime p divides n then p^2 must also divide n
(also called squareful, square full, square-full or 2-full numbers).
"""
for f in itertools2.unique(math2.prime_factors(n)):
if n%(f*f): return False
return True
def is_product_of_2_primes(n):
f=list(math2.prime_factors(n))
return len(f)==2 and f[0]!=f[1]
def is_product_of_2_primes(n):
f=list(math2.prime_factors(n))
return len(f)==2 and f[0]!=f[1]
