Simple calculation program for the 3x+1 problem

3n+1.py

import time

it = 0

L = []
i = 1
mi = 0
mv = 1
dt = time.time()
while i <= 1000000:
	d = time.time()
	j = i
	t = 0
	print('----= Checking ' + str(int(i)) + ' =----')
	while not j in L:
		if j == 1:
			break
		else:
			print('[iteration:' + str(it) + ']\tInserted:\t' + str(int(j)))
			L.append(int(j))

		if j % 2 == 0:
			j /= 2
		else:
			j = 3 * j + 1
		t += 1
		it += 1
	print('[iteration:' + str(it) + ']\tValidated ' + str(int(i)) + ' with ' + str(t) + ' iterations in ' + str(d - dt) + 's.')
	dt = d
	if t > mi:
		mi = t
		mv = i
	i += 1
	it += 1

print('-------------------------------------------------')
print('Max iterations for: ' + str(int(mv)) + ' in ' + str(mi) + ' iterations.')