google sheets – Merged cells autofilling


I have a sheet with merged cells in a column. Merged cells are of different sizes (not the same number of rows). I want to autofill this column, for example by typing “1” in the first one, then extend it down and get 2, 3, 4… But if tried that, the size of the first merged cell is also extended and all my cells get the same size… Which is not what I expect.

I also tried using a formula “=max(A$1:A1)+1” in the cell A2 and then using Ctrl+Enter to copy it in all the cells but the same issue arise : my merged cells get resized…

So my question is : is there an easy way to autofill merged cells of different size in Google Sheet ?