I'm trying to copy a formula in excel into many cells immediately below one another.

What I need is for each cell to be divided by ONE reference cell (whose value will change). The numerator for each cell will change based on the cell row, however.

To illustrate a different way:

A

1 1/A
2 2/A
3 3/A
4 4/A

This is what I'm trying to accomplish, but if I simply click the bottom-right corner of the first cell and drag to the bottom (I have hundreds of rows), A does not stay constant. It becomes B, C, D, and so on. If I input the formula manually into the first two rows and drag, I get

1 1/A
2 2/A
3 3/B
4 4/B

I hope my question is clear. Please ask for further clarification if needed. I'm just trying to avoid manually putting this formula into each cell. It seems there should be an easy solution.

Thank you!