def main():
known_prime_list = [2, 3, 5, 7]
known_truncatable_prime = list()
for i in prime_list(start_from=10):
if len(known_truncatable_prime) == 11:
print 'sum of all truncatable primes is {}'.format(
sum(known_truncatable_prime))
break
known_prime_list.append(i)
digit_len = len(str(i))
is_truncatable = True
#from left to right
for n in range(1, digit_len):
if int(str(i)[n:]) not in known_prime_list:
# print '{} is not truncatable because of {}'.format(i, int(str(i)[n:]))
is_truncatable = False
break
if is_truncatable:
for n in range(1, digit_len):
if int(str(i)[0:n]) not in known_prime_list:
#print '{} is not truncatable because of {}'.format(i, int(str(i)[0:n]))
break
else:
print 'found truncatable prime {}'.format(i)
known_truncatable_prime.append(i)
def prime_factorization(n):
num = n
sqr_root = int(math.sqrt(num))
factors = prime.prime_list(sqr_root)
prime_factor = []
for i in factors:
if i * i > num:
prime_factor.append(num)
return prime_factor
while num % i == 0:
num /= i
prime_factor.append(i)
if num == 1:
return prime_factor
prime_factor.append(num)
return prime_factor
def prime_factorization(n):
num = n
sqr_root = int(math.sqrt(num))
factors = prime.prime_list(sqr_root)
prime_factor = []
for i in factors:
if i*i > num:
prime_factor.append(num)
return prime_factor
while num%i == 0:
num /= i
prime_factor.append(i)
if num == 1:
return prime_factor
prime_factor.append(num)
return prime_factor
#-*- coding:utf-8 -*-
"""
The prime 41, can be written as the sum of six consecutive primes:
41 = 2 + 3 + 5 + 7 + 11 + 13
This is the longest sum of consecutive primes that adds to a prime below one-hundred.
The longest sum of consecutive primes below one-thousand that adds to a prime, contains 21 terms, and is equal to 953.
Which prime, below one-million, can be written as the sum of the most consecutive primes?
"""
import prime
primes = prime.prime_list(1000000)
primeSum = [0]*(len(primes)+1)
num = 0
for i in xrange(0, len(primes)):
primeSum[i+1] = primeSum[i] + primes[i]
for i in xrange(0, len(primes)):
j = i - (num + 1)
while j >= 0:
if primeSum[i] - primeSum[j] > 1000000:
break
if primeSum[i] - primeSum[j] in primes:
num = i - j
res = primeSum[i] - primeSum[j]
j -= 1
def test_prime_list_success(self):
result = prime_list(3)
self.assertEqual(list(result), [2,3,5])