Question 560244
After a bunch of painful calculations, I agree with all your numbers.
I also agree with all your classification, except that I do not know what to call social security numbers. The social security numbers I know have repetitions. Can someone have 111-11-1111 as a social security number? What about 000-00-0000? Maybe all such numbers are permissible, for a total of 10^9  possible social security numbers. Would you call it a permutation with replacement?