How many strictly descending numbers can be formed? For example: 643, 987632, 43, 1, .... but not 4332 or 984331. The largerst strictly descending number is 9876543210. I hope I made clear what I mean with strictly descending numbers. I would think there are 10^2 -1 possible numbers. Since the set of these numbers is basically the Powerset of {0,1,2,...,9}. Can someone confirm this is correct?
thanks in advance