I have data in sequentially numbered worksheets; such as "7-7-1", "7-7-2", etc.

I would like to compile data found in certain cells of these worksheets--the
same cell in each sheet.

Right now I start with something like "='7-7-1'!$O$45" and then just drag
down to copy and manually change the "7-7-1" part to "7-7-2" and so on.

Is there a way to do this more efficiently?

I have figured out how to use the CONCATENATE function to make a string that
matches the "='7-7-1'!$O$45" part, but I don't know how to use this further.

Any suggestions?