Excel shows row numbers on the side of the spreadsheet. But what if you want those numbers in a column?
This Microsoft Help page describes how to use the Row function:
Enter =row(A1) into the first cell of the column. Then copy the formula, and paste down the column. The formula should automatically adjust with each cell to reflect the row number. If you need to have actual numbers in there and not formula results, copy the column into Notepad, then copy the result in Notepad back into your column.
Another way: Python can do it very quickly.
j = (maximum number of rows, 40 or 200 or whatever you want, plus one)
i = 1
while i < j:
i = i + 1
The resulting output can be copied into Excel.