# How to shift the cell coordinate by constant number?

I want to pick 3000 data points from a large dataset. The data is placed in the cell, which coordinate constantly increase by number of 9. For instance the first data point of interest is in a cell A1, the second in A9, the third in A19. So how to make a formular to shift picking cell by 9 (something like that A1+9=A10, A10+9=A19 ....)?