Просто шукаємо прості числа:

import time

def prime_num1(n):

primes = list()

for num in range(1, n+1):

prime = True

for i in range(2, num):

if (num % i == 0):

prime = False

if prime:

primes.append(num)

return primes

start = time.time()

print(prime_num1(10000))

end = time.time()

print("elapsed time: "+str(end - start)+" sec")