Trying to figure out a mathematical representation of this sequence... I noticed that different patterns emerge when you subtract 1 from each value in the sequ

Trying to figure out a mathematical representation of this sequence... I noticed that different patterns emerge when you subtract 1 from each value in the sequence. From there we get: 0 1 2 4 16 160 15680 159591040 16866847940875520 Each (excluding 0 and 1) is a multiple of the previous term: 1 2 = 1 * 2 4 = 2 * 2 16 = 4 * 4 160 = 16 * 10 15680 = 160 * 98 159591040 = 15680 * 10178 16866847940875520 = 159591040 * 105687938 Anything ring a bell? Notice any other patterns?