Can anyone suggest a more elegant way of repeating a series of formulas than
the following? The most obvious problem (to me) is that if I have an
unexpected number of rows, I would run the formula past the used range.

I would also prefer not to use R1C1 notation, but when I tried I got
absolute cell references.

Thanks!

Sub tester()

' WORKS, BUT MAY ADD FORMULA PAST LAST ROW

With ActiveSheet
lstrow = Range("a" & Rows.Count).End(xlUp).Row
lstrow = lstrow - 2
Debug.Print lstrow
End With

Formula1 = "=SUM(RC[-3]:RC[-2])"
Formula2 = "=RC[-3]*RC[-2]"
Formula3 = "=RC[-3]/RC[-2]"

For i = 1 To lstrow Step 3
Cells(i, 4).FormulaR1C1 = Formula1
Cells(i + 1, 4).FormulaR1C1 = Formula2
Cells(i + 2, 4).FormulaR1C1 = Formula3
Next i
End Sub