def solve():
truncatable_primes = []
i = 1
while len(truncatable_primes) < 11:
if is_prime(i):
if i > 10:
str_i = str(i)
truncated_combinations = []
if len(str_i) >= 2:
# Get all forward/backward combinations
for pos, n in enumerate(str_i, start=1):
if pos == len(str_i):
break
truncated_combinations.append(str_i[pos:])
truncated_combinations.append(str_i[:-pos])
# Check if these numbers are all primes
can_add = not (not truncated_combinations) # False when list is empty
for n in truncated_combinations:
if not is_prime(int(n)):
can_add = False
break
if can_add:
truncatable_primes.append(i)
i += 1
print sum(truncatable_primes)
def find_nth_prime(n):
prime_list = set()
x = 1
while len(prime_list) < n:
if is_prime(x):
prime_list.add(x)
x += 1
return max(prime_list)
def test_problem_3(self):
from p003 import is_prime, func
self.assertEqual(is_prime(0), False)
self.assertEqual(is_prime(1), False)
self.assertEqual(is_prime(2), True)
self.assertEqual(is_prime(3), True)
self.assertEqual(is_prime(4), False)
self.assertEqual(is_prime(5), True)
self.assertEqual(is_prime(15), False)
self.assertEqual(is_prime(17), True)
self.assertEqual(func(14), 7)
self.assertEqual(func(13195), 29)
self.assertEqual(func(600851475143), 6857)
def find_prime_factorization(number):
all_factors = find_factors(number)
prime_factorization = []
if len(all_factors) == 1:
prime_factorization.extend([x for x in all_factors[0]])
else:
all_factors.remove((1, number))
factor_pair = all_factors.pop()
for f in factor_pair:
if is_prime(f):
prime_factorization.append(f)
elif f not in (1, number):
map(lambda x: prime_factorization.append(x), find_prime_factors(f))
return prime_factorization
import math
import time
from p003 import is_prime
if __name__ == '__main__':
start_time = time.time()
primes = [
2
] # initialize a list of prines collected. Start with first prime is 2
x = 10001 # want to find the xth prime
n = 3 # start at this
while len(
primes
) < x: # is the nth number on the list yet? +1 because array starts at zero
if is_prime(n):
primes.append(n) # adds that prime number to the list
n += 1 # increment to the next number
print("--- %s seconds ---" % (time.time() - start_time))
print(primes[-1])
