Write a function that returns the extended form of the prime factorization of a number. Return in the format [a, b, c, d, ...], where each element of the array is an integer.
prime_factorization(216) ➞ [2, 2, 2, 3, 3, 3]
prime_factorization(64) ➞ [2, 2, 2, 2, 2, 2]
prime_factorization(23) ➞ [23]N/A