#-------------------------------------------------------------------------------

# Name: Problem 7

# Purpose: What is the 10001st prime number?

#

# Author: Sebastián Torrente

#

# Created: 10/11/2012

# Comment: This one has no mistery, but is going to be useful in the future

#-------------------------------------------------------------------------------

def isprime(x):

"""Find if x is prime counting from n onwards."""

for divisor in range(2, int(x**0.5)+1):

if x / divisor == int(x / divisor):

return False

return True

def isprime2(n):

"""A version more optimized for future uses."""

n *= 1.0

if n % 2 == 0 and n != 2 or n % 3 == 0 and n != 3:

return False

for b in range(1,int((n**0.5+1)/6.0+1)):

if n%(6*b-1)==0:

return False

if n %(6*b+1)==0:

return False

return True

def primelist(n):

"""Return a list with the first n prime numbers."""

listprim=[2,3,5,7,11,13,17,19] #Let's put some of them to save a little bit

#of brainpower.

init = 23

while len(listprim) < n:

if isprime2(init) == True: listprim.append(init)

init += 1

return listprim

if __name__ == '__main__':

print (primelist(10001)[-1])

# print(isprime(23))