Construct a diagram with your row of six as underscores

___ X ___ X ___ X ___ X ___ X ___

The first underscore can have any of the three integers

3 X ____ X ____ X ____ X ____ X ____

The second underscore can have any of the remaining two integers

3 X 2 X ____ X ____ X ____ X ____

The remaining underscore can be filled with the integer 2, since the possibilities are the integers that are not the one integer to the left of it.

so 3 X 2 X 2 X 2 X 2 X 2 = 3 * 2^5 = 96