Splitting N! into N factors is trivial. It’s defined as the product of N integers, the integers 1 through N. Can you still split N! into N factors if you put a minimum size requirement on the factors? You can’t split 3! into three factors unless one of the factors is 1, but you can split 4! into factors ≥ 2: 4! […] The post Refactoring factorials first appeared on John D. Cook.