Function nbOccurence(nb, plage As Range) As Long
Dim c As Range, nbr As Long, s As String, i As Long
For Each c In plage
i = i + 1
If c.Value <> s Then
If nbr = nb Then nbOccurence = nbOccurence + 1
nbr = 1
Else
nbr = nbr + 1
End If
If i = plage.Cells.Count And nbr = nb Then
nbOccurence = nbOccurence + 1
End If
s = c.Value
Next c
End Function