Range("A:A, C:C, E:E").Columns.HorizontalAlignment = xlCenter
Par contre pour l'automatisation sur une plage, attendons les pros...
Sub Centrer()
Dim P As Range, i As Integer
Set P = [B2:Z100] 'à adapter
P.HorizontalAlignment = xlGeneral
For i = 1 To P.Columns.Count Step 2
P.Columns(i).HorizontalAlignment = xlCenter
Next
End Sub
Sub Centre_Selection_1_Colonne_sur_2()
For i = ActiveCell.Column To ((Selection.Columns.Count + ActiveCell.Column)) Step 2
Columns(i).HorizontalAlignment = xlCenter
Next
End Sub
Sub Centre_Selection_1_Colonne_sur_2()
For i = Selection.Column To Selection.Columns.Count + Selection.Column - 1 Step 2
Columns(i).HorizontalAlignment = xlCenter
Next
End Sub
Sub Centre_Selection_1_Colonne_sur_2()
For i = 1 To Selection.Columns.Count Step 2
Selection.Columns(i).HorizontalAlignment = xlCenter
Next
End Sub