Concatenate macro Type Mismatch error

Newbie to macros and VBA here. I am attempting to concatenate several columns and I am getting the Type Mismatch error. I understand why I am getting this error, but I do not know any other way to accomplish what I am seeking. Any help would be greatly appreciated.

Sub Concatenate
    LR = Range("A1").End(xlDown).Offset(1, 0).Row
    Range("AA1").Select
    ActiveCell.FormulaR1C1 = "Combined Account"
    Selection.Font.Bold = True
    Range("AA2:AA" & Range("A" & Rows.Count).End(3)(1).Row).FormulaR1C1 = _
    "=CONCATENATE(A1,"-",R1,"-",S1,"-",T1,"-",G1)"       'type mismatch error pops here
    Range("AA2:AA" & LR).Value = Range("AA2:AA" & LR).Value
    Range("A1").Select
End Sub

Thanks in advance,
Ray