Hi,
perhaps this is what you want:

In cell A1 enter: 1
In cell A2 enter: =A1+1

Now goto cell a85000 (one quick way of doing this is pressing F5 and then enter a85000 + "OK")

Now hold down the shift key (don't release it!)
Press the button "End" once
Press the button "arrow up" once.
Now you can release the shift key.

You have now marked the area a2:a85000
Now press CTRL+D (or menu: Edit / Fill / Down)

Now you have numbers 1-85000 in the cells a1:a85000.

If you like to avoid formulas in these cells, do the following.
You should still have the area a2:a85000 marked.
Press CTRL+C
Select menu: Edit / Paste special / values.

Best regards
Bjorn