I want to add to this formula an additional function that if any cells in column A1 are blank, then do not perform the remainder of the equation.
Is this the same column that you are looking up in?
=IF(COUNTIF(
lookup!A:A,N2)>0, "Exclude", "Not In Lookup")
I'm not sure I see a solution - normally I'd suggest a dynamic range so you could count the blanks, but usually a dynamic range is based on the count of the values and assumes there are no blanks (!) -- so we end up where we started with the same problem. The entire Column A:A will have blanks in it so we need to know where to cut it off when checking for blanks.
Why would you have blanks in a lookup anyway? Maybe there's a better way to do this. MATCH OR VLOOKUP would search for an exact match, for instance, so you'd know a value was empty if it returned an NA error:
=IF(ISNA(MATCH(N2,Lookup!A:A,0)), "Exclude", "Not In Lookup")
Or if you need those zero counts, then maybe:
=IF(ISNA(MATCH(N2,Lookup!A:A,0)),"oops!",IF(COUNTIF(lookup!A:A,N2)>0, "Exclude", "Zero Count!"))