Primes over 300

The answer is 479 .

One solution is to iterate through the integers starting at 300, checking if each one is prime. Keep a counter of how many primes have been encountered. Once the counter reaches 30, you have reached the answer.

There are many ways to determine if a number n is prime. The below solution uses the sieve of Eratosthenes as its approach.

# Python solution

import math

# isPrime(n): Determines whether n is prime using the sieve of Eratosthenes
# returns True or False
def isPrime(n):
    if (n == 1):
        return False
    elif (n < 4):
        return True
    elif (n % 2 == 0):
        return False
    elif (n < 9):
        return True
    elif (n % 3 == 0):
        return False
    else:
        r = math.floor(math.sqrt(n))
        f = 5
        while (f <= r):
            if (n % f == 0):
                return False
            if (n % (f+2) == 0):
                return False
            f += 6
        return True

# loop through the numbers above 300
# check each one to see if it is prime
# when you find the 30th prime, print it out
n = 300
count = 0
while (count < 30):
    if isPrime(n):
        count += 1 
        n += 1
    else:
        n += 1
print n - 1