Type ROW A1 into the cell if it is cell A1. I start with an equals sign click a cell that I want to add then a plus sign and then another cell and press Enter. Enter 1 in cell A2.
If your selection is on the first empty cell under a column when you press the AUTOSUM button Excel will assume that you want to add all the numbers in that column and place the result in the empty cell.
In each linear series you add or subtract the same step value. Scroll down and select the footer where you want to insert the page numbers in Excel. How to create sequential number in Excel FAST. Fill a column with a series of numbers.