One Line Code Challenge: compute the list of prime factors

factors = lambda n, k=2: ([k] + factors(n / k) if n % k == 0 else factors(n, k+1)) if n > 1 else []


In[17]: factors(3)
Out[17]: [3]
In[18]: factors(4)
Out[18]: [2, 2]
In[19]: factors(9)
Out[19]: [3, 3]
In[20]: factors(18)
Out[20]: [2, 3, 3]
In[21]: factors(24)
Out[21]: [2, 2, 2, 3]
In[22]: factors(1)
Out[22]: []