def is_pandigital_product(x, y):
product_string = str(x) + str(y) + str(x*y)
if len(product_string) != 9: return False
return is_pandigital(int(product_string))
def forms_pandigital(n):
concat = str(n)
for i in itertools.count(2):
concat += str(n*i)
if len(concat) == 9 and is_pandigital(int(concat)): return int(concat)
elif len(concat) > 9: return 0