Function logfact(N)
    If N <= 170 Then
       factout = Application.WorksheetFunction.Fact(N)
       sumout = Log(factout)
    Else
       factout = Application.WorksheetFunction.Fact(170)
       sumout = Log(factout)
       For i = 171 To N
          sumout = sumout + Log(i)
       Next i
    End If
    logfact = sumout
End Function