The set of digits, in most instances, can be the number of combinations of 10 things (the digits) taken 1, 2, 3, 4 or 5 at a time. For example 71803 is in the same class as 30178. The only exception to this is numbers consisting solely of zeros--they are not in the range. The other single-digit classes each have two members, such as {1111, 11111} or {9999, 99999}.
n C(10,n)
1 10 - 1 = 9
2 45
3 120
4 210
5 252
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637 - 1 = 636
There are 636 equivalence classes.
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Posted by Charlie
on 2021-06-22 10:42:59 |
solution
