• Source 
    1. n = int(raw_input())
    2. prime_factors = []
    3. start = 2
    4. while start*start <= n:
    5. 	if n % start == 0:
    6. 		expo = 0
    7. 		while n % start == 0:
    8. 			expo = expo + 1
    9.  			n = n / start
    10.  		prime_factors.append([start,expo])
    11. 	start = start + 1
    12.  
    13. if n > 1:
    14. 	prime_factors.append([n,1])
    15. print prime_factors