from matplotlib.pylab import *

def fib1(n):
    if n <= 1: return n
    return fib1(n-1)+fib1(n-2)

def fib2(n, a=0, b=1):
    if n == 0: return a
    elif n == 1: return b
    else: return fib2(n-1, b, a+b)

# Plotten der Fibonacci-Reihe
fibs = []
for i in range(1,40):
    fibs.append(fib2(i))

semilogy(fibs, 'o-')
show()