Sub insere()
With Columns(6).Resize(, [A1] * 2)
.Insert Shift:=xlToRight
.Offset(, -[A1] * 2).Resize(, [A1] * 2).ColumnWidth = 5
.Offset(, -[A1] * 2).Resize(, [A1] * 2).HorizontalAlignment = xlCenter
End With
For i = 1 To [A1] * 2
For Each c In Array("AM", "PM")
Cells(3, 5 + i) = c: i = i + 1
Next c
i = i - 1
Next i
End Sub