Verify if 0 + 1 + 2 + ... + n is equals to (n * (n + 1)) / 2 by exhaustion

exhaustion

#!/usr/bin/env python

from time import time

'''
	Verify if 0 + 1 + 2 + ... + n is equals to (n * (n + 1)) / 2, this 
	method is not using mathematical induction, it is using exhaustion
'''
def proof(n):
	for i in range(n + 1):
		s = 0
		for j in range(i + 1):
			s = s + j
		if (s != ((i * (i + 1)) / 2)):
			return False
	return True

start = time()
print proof(10), "Spent {} milliseconds".format(time() - start)