Sub test()
Set CelDepart = Sheets("Feuil1").Range("A4")
MaSemaine = 1 * Mid(CelDepart.Value, 5, 2)
MonAnnee = 1 * Right(CelDepart.Value, 4)
MonLundi = DateSerial(MonAnnee, 1, 4) - Weekday(DateSerial(MonAnnee, 1, 4), 3) + 7 * (MaSemaine - 1)
For i = 0 To 6
CelDepart.Offset(i, 2).Value = MonLundi + i
Next i
End Sub