Conditional product

Hi Excel forum,

I'm a relatively newbie user trying to do the following:

Multiply each value in A1:20 by each value in B1:20 and sum them all, EXCEPT for A1*B1, A2*B2, etc. Such that we have A1*B2 + A1*B3 +...+ A2*B1 + A2*B3 +...

I imagine it's a simple fix I can't figure out how to do it for the life of me using array functions >_< Will I have to get into the VBA code? I have yet to explore that realm..

Thanks in advance.

will this macro help you

Sub test()
Dim j As Long, k As Long, ssum As Double
k = 1
ssum = 0
Do
For j = 1 To Range("A1").End(xlDown).Row
ssum = ssum + Cells(j, 1) * Cells(j, 1).Offset(k, 1)
Next j
k = k + 1
If k > Range("B1").End(xlDown).Row Then Exit Do
Loop
MsgBox ssum
End Sub

This maby?

Sub steffen()

For Each xCell In Range("A1:A20")
    cRow = xCell.Row
    For i = 1 To 20
        If i = cRow Then
            ' Do nothing
        Else
            Total = Total + (xCell * Cells(cRow, 2))
        End If
    Next i
Next xCell

MsgBox (Total)

End Sub