def sum_of_even_fibonacci_numbers(limit):
"""
finds the sum of even Fibonacci numbers up to some limit, inclusive
limit (int): max number
returns (int): sum
"""
even_fibs = []
for fib in gen_fibonacci():
if fib > limit:
break
elif is_even(fib):
even_fibs.append(fib)
#print("+ " + str(fib))
else:
continue
return sum(even_fibs)
def is_goldbach_number(number):
"""
>>> is_goldbach_number(9)
True
>>> is_goldbach_number(15)
True
>>> is_goldbach_number(5777)
False
"""
primes = Primes(number)
for prime in primes:
step = number - prime
if is_even(step):
step = sqrt(step / 2)
if is_integer(step):
return True
return False
