Sub Test()
Dim x() As Variant, i%, j%, n%, m%, flag As Boolean, p As Variant, encuentra As Variant, Rango As Range
  Set Rango = Application.InputBox(Prompt:="Valor", Type:=8)
  n = Rango.Rows.Count
  m = Rango.Columns.Count
  flag = True
ReDim x(n, m)
 x = Application.Munit(n * m)
   For i = 1 To n
    For j = 1 To m
   Do While flag = True
   Randomize
    p = Application.RandBetween(1, n * m)
   x(i, j) = p
  encuentra = Application.CountIf(x, p)
   If encuentra = 1 Then
  x(i, j) = p
   flag = False
    Else
     Randomize
      p = Application.RandBetween(1, n * m)
    flag = True
   End If
   Loop
  Next j
 Next i
End Sub