hi, JAM !

IMHO... if you start an autonumbering list [i.e.] in 'A5' with the suggested formula: =1+row()-5
the starting/following numbers will fail if you insert row/s above 'A5'

[using same example, starting autonumber in 'A5'] try with: =rows($b$5:b5) [and copy/drag down]
this will fail also if you delete column 'B'

another possibility is: type 1 in your 'starting' autonumber cell [say 'A5']
and use the following starting formula below: =offset(a6,-1,0)+1

hth,
hector.

Excel provides some help on AutoNumbeing by filling in series or using ROW formula.
Well both have negative point thar they do not update when you add, remove or modify rows.
Well, using a different kind of ROW formula given below you can make your autonumber update when you add, modify or remove row.
The formula is '=1+ROW()-1'. Insert this formula where you want the first autonumber to come.
You will have to change the last offset to suit the number of row you left from top.
ex. If you want to start autonumbeing from 3rd row put '=1+ROW()-3' then fill in the series till you want to.
If you insert any row inbetween you will have to fill just that series.
The belownumber will be updated. If you remove all number are updated.
If you cut a row and insert in below, if will be inserted updated with you only have to fill series the inserted blank one.