I am trying to figure out the number of possible combinations which I can arrange this sequence:

123456

where:

4 can also be X

5 can also be Y

6 can also be Z

For example, 1 combination can be:

12345Z

Is the proper equation combinations = (n^n) -1

where n is the number of variables that can be change?

For my example I think think the number of combinations would be 8

(3^3) -1

Thanks for any help!

Mr. EKO