Prof Loh's suggestion
First tells you how efficient recursion is
Then tells you how much multiplication and division you have to do in the casework method
Prof Loh: "So you can choose whichever one is more efficient for you"
@debbie actually I think this should go in the "funny" section of the General Discussion.
@rz923 Lol, an understated joke I'm very happy to move it over to there!