Réduire un code

Option Explicit
Private Sub Worksheet_SelectionChange(ByVal c As Range)
    Dim plage As Range
    Set plage = Range("AH12,AH16,AH18,AH20,AH26,AH28,AH30,AH32,AH34,AH36,AH38,AH40,AH42,AH46,AH48,AH52,AH54,AH58,AH60,AH62,AH66")
    For Each c In plage
        If c = "" Then c = "En cours"
    Next
End Sub

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim r As Range
Set r = [AH12,AH16,AH18,AH20,AH26,AH28,AH30,AH32,AH34,AH36,AH38,AH40,AH42,AH46,AH48,AH52,AH54,AH58,AH60,AH62,AH66]
For Each r In r
  If r = "" Then r = "En cours"
Next
End Sub

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim a, i
a = Array(12, 16, 18, 20, 26, 28, 30, 32, 34, 36, 38, 40, 42, 46, 48, 52, 54, 58, 60, 62, 66)
For i = 0 To UBound(a)
  If Range("AH" & a(i)) = "" Then Range("AH" & a(i)) = "En cours"
Next
End Sub

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim a, i
a = Array(14, 22, 24, 44, 50, 56, 64)
For i = 12 To 66 Step 2
  If IsError(Application.Match(i, a, 0)) And _
    Range("AH" & i) = "" Then Range("AH" & i) = "En cours"
Next
End Sub