Numbers can be regarded as the product of their factors. For example, 8 = 2 x 2 x 2 = 2 x 4. Given an integer n, return all possible combinations of its factors. You may return the answer in any order. Note that the factors should be in the range [2, n - 1]. Example 1: Input: n = 1 Output: [] Example 2: Input: n = 12 Output: [[2,6],[3,4],[2,2,3]] Example 3: Input: n = 37 Output: [] Example 4: Input: n = 32 Output: [[2,16],[4,8],[2,2,8],[2,4,4],[2,2,2,4],[2,2,2,2,2]] Constraints: 1 <= n <= 108