Sub GenerateRandomNumbers()
  Dim iRundNum As Integer, iMinNum As Integer, iMaxNum As Integer
  Dim rngTab As Range, rngCell As Range
'
  iMinNum = 1: iMaxNum = 25
  Set rngTab = Range("B2:F6")
  For Each rngCell In rngTab
    Randomize
    iRundNum = Int(iMinNum + (Rnd() * iMaxNum))
    rngCell.Value = iRundNum
  Next
  Set rngCell = Nothing
  Set rngTab = Nothing
End Sub

Public Sub Test()
 Dim ar() As Long
 Dim Size As Long
 Dim i As Long
 Dim j As Long
 Dim tmp As Long
 
 Size = 25
 ReDim ar(1 To Size) As Long
 
 For i = 1 To Size
    ar(i) = i
 Next i
 
 Randomize

 For i = 1 To Size
    j = Int((Size - i + 1) * Rnd + i) 'перемешивать надо хвост массива
    tmp = ar(i)
    ar(i) = ar(j)
    ar(j) = tmp
 Next i

 'далее вывод ar() на лист, например
End Sub