comment concatener via VBA une liste Variable

Sub essaimacro()
Dim i As Integer
Dim St As String
Application.ScreenUpdating = False
finnn = Range("a65536").End(xlUp).Row
For i = 1 To finnn
    If Range("A" & i) <> "" Then St = St & "%2B" & Range("A" & i)
Next i
Range("B1") = St
End Sub

Sub ConcatListe()
  With Sheets("Feuil1")
    .[b1] = Concat(.Range(.[a1], .Cells(.Rows.Count, "a").End(xlUp)), "%2B")
  End With
End Sub

Function Concat$(x As Range, sep$)
Dim t, i
  With Sheets("Feuil1")
    t = x.Value
  End With
  Concat = sep
  For i = 1 To UBound(t)
    Concat = Concat & t(i, 1) & sep
  Next i
End Function

=concat(A1:A3;"%2B")

Sub toto()
Dim n&, t$
  With [A1]
    For n = 0 To .Offset(Rows.Count - .Row).End(xlUp).Row - .Row
      If Not IsEmpty(.Offset(n).Value) Then t = t & .Offset(n).Value & "%2B"
    Next
    If t <> "" Then t = "%2" & t
    .Offset(, 1).Value = t
  End With
End Sub

Function tata$(Cel As Range, prefX$, suffX$)
Dim n&
  Application.Volatile
  With Cel
    For n = 0 To .Offset(Rows.Count - .Row).End(xlUp).Row - .Row
      If Not IsEmpty(.Offset(n).Value) Then tata = tata & .Offset(n).Value & suffX
    Next
    If tata <> "" Then tata = prefX & tata
  End With
End Function

Function tutu$(Plg As Range, prefX$, suffX$)
Dim Cel As Range
  For Each Cel In Plg.Cells
    If Not IsEmpty(Cel.Value) Then tutu = tutu & Cel.Value & suffX
  Next
  If tutu <> "" Then tutu = prefX & tutu
End Function

Function titi$(Plg As Range, prefX$, suffX$)
Dim i&, j&, p
  p = Plg.Value
  If VarType(p) > vbArray Then
    For i = 1 To UBound(p): For j = 1 To UBound(p, 2)
      If Not IsEmpty(p(i, j)) Then titi = titi & p(i, j) & suffX
    Next j, i
  Else
    If p <> "" Then titi = p & suffX
  End If
  If titi <> "" Then titi = prefX & titi
End Function