Poked around on the google[0]: def fib(n): a, b = 0, 1 for _ in range(n): a, b = b, a + b return b No itertools, not overly complex, no

Poked around on the google[0]: def fib(n): a, b = 0, 1 for _ in range(n): a, b = b, a + b return b No itertools, not overly complex, no tail recursion. If you were careful of the scoping rules something like foo(get_next(i) for i in whatever()) could be made to work without too much trouble (also without itertools) if you needed a sequence. Probably just throw a lambda in there instead of get_next and python would be happy, too lazy to work it out. [0]http://www.koderdojo.com/blog/python-fibonacci-number-generator http://www.koderdojo.com/blog/python-fibonacci-number-genera... --edit-- Actually, I think this function gives the wrong result for 0 and maybe 1, just copypasta'd the code so blame them...