Returns the number of ordered permutations, allowing repetition.
where n and k are integers.
PERMUTATIONA returns the number of ordered ways that k objects can be chosen from a set of n objects, where an object can be chosen repeatedly. For example with a set of 3 objects A, B, C, we can choose 2 as follows: AA, AB, AC, BA, BB, BC, CA, CB, CC.
PERMUTATIONA simply calculates .
returns 9, as in the example above.