Check it out... def fibonacci_sequence(): a, b, c = 0, 0, 1 while True: a = b; b = c; c = a + b yield b

Check it out... def fibonacci_sequence(): a, b, c = 0, 0, 1 while True: a = b; b = c; c = a + b yield b >>> fibonacci_sequence() <generator object fibonacci_sequence at 0x108055550> >>> list(itertools.islice(fibonacci_sequence(), 0, 10)) [1, 1, 2, 3, 5, 8, 13, 21, 34, 55] >>> for n in fibonacci_sequence(): print n if n > 13: break 1 1 2 3 5 8 13 21 >>>