def primeFactors(n):
"""a list of prime factors of n"""
result = []
upper_bound = 1 +int(n**0.5) # only have to seek to the square root
searchList = primes(upper_bound)
for divisor in searchList:
if divides(divisor, n):
result.append(divisor)
result += primeFactors(int(n // divisor))
break
# no factors found, so assume prime.
if result == []:
result.append(n)
return result
def euler_p1():
return sum(filter(lambda x: divides(3,x) or divides(5,x), range(1000)))