[bigpooch]

The following gives a count of all 3 number combinations of
11 digit sequences.

10 sequences with exactly 1 digit represented

C(10,2) x (2^11 - 2) = 92070 sequences with exactly 2 digits
represented

C(10,3) x (3^11 - 3(2^11-2) - 3) = 20520720 sequences with
exactly 3 digits represented

the total is 20612800 which verifies the answer given by
M.B.E. in a previous post.