Vérifier l'existence d'une valeur dans un classeur et l'existence d'une feuille

Sub test()
Dim i As Integer, existe As Boolean, noFeuilleRecherche As Integer, celluleValeur As Range, feuille
With ThisWorkbook.Sheets("Table")
    For i = 2 To .Cells(.Rows.Count, 1).End(xlUp).Row
        existe = False
        For noFeuilleRecherche = 1 To 3
            Set celluleValeur = Nothing
            Set celluleValeur = ThisWorkbook.Sheets(CStr(noFeuilleRecherche)).Cells.Find(what:=.Cells(i, 1).Value, LookIn:=xlValues, lookat:=xlWhole)
            If Not celluleValeur Is Nothing Then existe = True
        Next noFeuilleRecherche
        If existe Then
            .Cells(i, 2).Value = "KO"
            For noFeuilleRecherche = 1 To ThisWorkbook.Sheets.Count
                If ThisWorkbook.Sheets(noFeuilleRecherche).Name = .Cells(i, 1).Value Then .Cells(i, 2).Value = "OK"
            Next noFeuilleRecherche
        End If
    Next i
End With
End Sub

For noFeuilleRecherche = Lun To Mer

Sub test()
Dim i As Integer, existe As Boolean, noFeuilleRecherche As Integer, celluleValeur As Range

Dim feuilles(3) As String
feuilles(1) = "Lun"
feuilles(2) = "Mar"
feuilles(3) = "Mer"

With ThisWorkbook.Sheets("Table")
    For i = 2 To .Cells(.Rows.Count, 1).End(xlUp).Row
        existe = False
        For noFeuilleRecherche = 1 To UBound(feuilles)
            Set celluleValeur = Nothing
            Set celluleValeur = ThisWorkbook.Sheets(feuilles(noFeuilleRecherche)).Cells.Find(what:=.Cells(i, 1).Value, LookIn:=xlValues, lookat:=xlWhole)
            If Not celluleValeur Is Nothing Then existe = True
        Next noFeuilleRecherche
        If existe Then
            .Cells(i, 2).Value = "KO"
            For noFeuilleRecherche = 1 To ThisWorkbook.Sheets.Count
                If ThisWorkbook.Sheets(noFeuilleRecherche).Name = .Cells(i, 1).Value Then .Cells(i, 2).Value = "OK"
            Next noFeuilleRecherche
        End If
    Next i
End With
End Sub