RosettaCodeData/Task/Hamming-numbers/Python/hamming-numbers-5.py

from heapq import merge
from itertools import tee

def hamming_numbers():
    last = 1
    yield last

    a,b,c = tee(hamming_numbers(), 3)

    for n in merge((2*i for i in a), (3*i for i in b), (5*i for i in c)):
        if n != last:
            yield n
            last = n