Does anyone know why this code

ActiveCell.FormulaR1C1 = "=HLOOKUP(A20,RC[1]:RC[100],1,FALSE)"

becomes this in the cell once inserted

=HLOOKUP('A20',RC[1]:RC[100],1,FALSE)

and the "added" apostrophes to cell ref 'A20' instead of A20 prevent the A20
text from being found by the HLOOKUP. If after inserted I manually remove
the apostrophes, the command works properly. How can I prevent VBA from
adding these apostrophes??