In the Insert Sequence Number dialog box click New button to expand the dialog. In the first cell of the range that you want to number type ROW A1. SEQUENCE rows columns start step Rows - the number of rows to fill with dates.
You can also add many cells this way not just two.
Type ROW A1 into the cell if it is cell A1. Enter 1 in cell A2. Use the ROW function to number rows. Select Fill drop-down - Series Series dialog box will appear.