This formula is meant to count independent entries in A1:A20.
=ROUND(SUMPRODUCT(1/COUNTIF(A1:A20,A1:A20)),0)

Can anyone make this better? I am not talking about using Absolute
references, but ways to modify it so it works in every case. For instance,
at first I had an empty cell in my range and the #DIV/0 error was returned.
I don't fully understand the two negatives in front of some formulas, but I
am wondering if that would work better, too?
=ROUND(SUMPRODUCT(1/--COUNTIF(A1:A20,A1:A20)),0)

Thanks for any help.
-- Brad E.