Easiest way would be to use Ctrl+G (GoTo) and select Visible Cells only. You will want to highlight ONLY the data you want to replace with the formula.

So, if you want to replace all visible cells from A2:A500, then:
1. write your formula in a cell
2. copy the cell that contains the formula
3. select your range (for the example, we'll say A2:A500)
4. hit Ctrl+G to open GoTo
5. select Visible Cells and click OK
6. hit Ctrl+V to paste the formula in all those cells selected

Hope that helps!