Option Explicit

Sub test()
    Dim lastrow  As Long
    Dim i As Long
    Dim n As Long

    lastrow = Cells(Rows.Count, 2).End(xlUp).Row
    
    For i = 2 To lastrow
        Cells(i, "d").Value = n Mod 5 + 1
        n = n + 1
    Next

End Sub