Increment count by from the previous count only when there is a value

if column F does not have a value, do you want a blank in column A or do you want the previous value in column A repeated?

if you want Col A blank when F is blank:

=IF(ISNUMBER(F2),MAX(A$1:A1)+1,"")

if you want the previous value from Col A repeated when F is blank:

=IF(ISNUMBER(F2),MAX(A$1:A1)+1,MAX(A$1:A1))

Both of these are intended to be entered in cell A2 and filled down.

If you want the previous value from Col A repeated when F is blank, you may also try this formula for A2:

=IF(ISNUMBER(F2),A1+1,A1)

Drag and fill down for the rest of the cells in column A.

Thank you Clownfish and Ikuogs.

FYI - I wanted blanks on A cells when there is no value on F cells.