If you right-click, edit the pattern feature, the number of pattern members will show up as one of the editable items.
Click the Swap Dimensions icon
and you will see the names of the dimensions. The number of pattern members in each direction is always a 'pxxx' number, p301, or p12, or something like that.
In a drawing, you can use that number directly in a note by typing '&p12 holes ...etc.'.
The problem comes when your pattern has more than one direction. There is no single parameter for 'p1 + p2'. If you want a parametric note in yur drawing for the total number of holes in a p1 x p2 pattern, you will need to create a parameter no_of_holes in the part and use a relation to make no_of_holes=p1+p2.
Conversely, if you want to use a parameter to drive the number of holes in a given direction in your part, make the pattern and identify the 'pxx' number as before, then make a parameter I_want_this_many_holes in your part and use a relation to make p1=I_want_this_many_holes.
I hope this helps.
The answer is that you cannot do this directly, but the value in your image can be driven by parameters and relations. It just requires a separate step to manipulate this value.