What is the explicit rule for this table?

This is a geometric series of the general form
nth term=ar^(n-1)
with the first term a=375, and the common ratio r=1.5

NB the numbers to the left of the vertical line unusually imply that in this case n=o for the first term. Using that particular format the normal rule would be modified to
nth term = ar^n
where n is the number to the left of the vertical.

Okay, I understand now. Thanks!