# Seen here: http://stackoverflow.com/questions/16996217/prime-factorization-list def factorize(n): primfac = [] d = 2 while d*d <= n: while (n % d) == 0: primfac.append(d) # supposing you want multiple factors repeated n //= d d += 1 if n > 1: primfac.append(n) return primfac