Visual Basic - Excel,, Generar números aleatorios en un rango

Option Explicit

Sub Crear_Numeros()

    Dim Tabla(15) As Integer, a As Integer, b As Integer, _

        Existe As Boolean, Pun As Integer, Num As Integer, _

        Lin As Integer, Col As Integer

    Randomize Timer: Pun = 0

    For a = 1 To 15

        Num = Int(Rnd * 1000) + 1: Existe = False

        For b = 1 To Pun

            If Tabla(b) = Num Then Existe = True

        Next

        If Not Existe Then Pun = Pun + 1: Tabla(Pun) = Num

    Next

    Pun = 1

    While Pun < 15

        Lin = Int(Rnd * 16) + 6

        Col = Int(Rnd * 16) + 12

        If Cells(Lin, Col) = "" Then

           Cells(Lin, Col) = Tabla(Pun): Pun = Pun + 1

        End If

    Wend

End Sub