gistfile1.py

description = '''
By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6^(th) prime is 13.

What is the 10001^(st) prime number?
'''


# modifying our sieve

from __future__ import division

def gen_primes(n_primes):
    ''' this is a sieve of eratosthenes approach
    could use a wheel for better (faster) performance
    '''
    primes = []
    n = 1
    while len(primes) < n_primes:
        n += 1
        good = True
        for x in primes:
            if n % x == 0:  
                good = False
                break
        if good:
            yield n   # yield before we append, so that we don't 
                       # have to go up to the next prime before we can exit.
            primes.append(n)   

P = list(gen_primes(10001))
print P[-1]
# 104743