Sub nn()    
    Set sel_col = Application.InputBox("Выделите столбцы, к-е необходимо дублировать:", "Столбцы", Type:=8)
    kolvo = Application.InputBox("Сколько раз дублировать?", "Дубли")    
    Set dic_columns = CreateObject("Scripting.Dictionary")    
    For Each col In sel_col
        dic_columns.Item(col.Column) = col.Column
    Next    
    llastrow = Cells.SpecialCells(xlLastCell).Row
    stroki = dic_columns.items
    QuickSort stroki, 0, UBound(stroki)
    Application.ScreenUpdating = False
    For i = UBound(stroki) To 0 Step -1
        For j = 1 To kolvo
            Columns(stroki(i)).Copy
            Columns(stroki(i) + j).Insert Shift:=xlToRight
            Range(Cells(1, stroki(i) + j), Cells(llastrow, stroki(i) + j)).FormulaLocal = Range(Cells(1, stroki(i)), Cells(llastrow, stroki(i))).FormulaLocal
        Next
    Next i
    Application.CutCopyMode = False
    Application.ScreenUpdating = True   
End Sub

Public Sub QuickSort(vArray As Variant, inLow As Long, inHi As Long)
  Dim pivot   As Variant
  Dim tmpSwap As Variant
  Dim tmpLow  As Long
  Dim tmpHi   As Long
  tmpLow = inLow
  tmpHi = inHi
  pivot = vArray((inLow + inHi) \ 2)
  While (tmpLow <= tmpHi)
     While (vArray(tmpLow) < pivot And tmpLow < inHi)
        tmpLow = tmpLow + 1
     Wend
     While (pivot < vArray(tmpHi) And tmpHi > inLow)
        tmpHi = tmpHi - 1
     Wend
     If (tmpLow <= tmpHi) Then
        tmpSwap = vArray(tmpLow)
        vArray(tmpLow) = vArray(tmpHi)
        vArray(tmpHi) = tmpSwap
        tmpLow = tmpLow + 1
        tmpHi = tmpHi - 1
     End If
  Wend
  If (inLow < tmpHi) Then QuickSort vArray, inLow, tmpHi
  If (tmpLow < inHi) Then QuickSort vArray, tmpLow, inHi
End Sub