>>> def fib_to(n):
... fibs = [0, 1]
... for i in range(2, n+1):
... fibs.append(fibs[-1] + fibs[-2])
... return fibs
...
>>> def fib(n, computed = {0: 0, 1: 1}):
... if n not in computed:
... computed[n] = fib(n-1, computed) + fib(n-2, computed)
... return computed[n]