import numpy as np



def colloratz(numb):
        if numb%2==0:
                return (numb/2)
        else:
                return (3*numb+1)


vec = []

for numb in xrange(2,10*3):
        cnt=0
        while numb is not 1:
                numb=colloratz(numb)
                cnt+=1
        vec.append(cnt)
np.histogram(vec)