Scanning down a column
 

I want to scan down a data series in a column and look at the value of
each cell in cell G4.
I can do this in a Macro, but I would like to do it with formula using
Function Key F9.
e.f. Formula in Range("G4") = "=A1" will advance to
Range("G4") = "=A2",
Range("G4") = "=A3" and so on with each calculation.
To begin, I will have
Range("G2") = "=G1 + 1" : Range("G1") = "=G2" which are circular.
Formula in Range("G4") will look something like
Range("G2") = "=A" & Range("G1")
Thanks