3 ms·
N!! is the usual notation, so 3!! = 3, 4!! = 8, 5!! = 15, 6!! = 48, etc. It’s a bit unfortunate, because you’d think it meant iterating the factorial, so 3!! =
by madcaptenor 2y ago
N!! is the usual notation, so 3!! = 3, 4!! = 8, 5!! = 15, 6!! = 48, etc.
It’s a bit unfortunate, because you’d think it meant iterating the factorial, so 3!! = 720, etc. But there are basically no situations where you want to do that.