I have a list where I need to identify if the TicketNumber cell contains invalid numbers. Examples of valid numbers are: 1563447, VT12645895, VT#8564466. Samples of invalid numbers are: 11111111, 11122222, VT111111, VT1112222, NA or "not available". The alphas are ok only if they appear on a separate list of valid alpha characters. I know that accuracy will be something that cannot be guaranteed, but at least I can narrow down from thousands to a few hundreds