The below formula searches for duplicates in a column labeled 'pin' and adds a one to a 1 to a column named flag when duplicates are found.
=IF(COUNTIFS(Pin$1:Pin@row, Pin@row) > 1, 1)
I need a formula that does this but turns the 1 into a smartsheets symbol or maybe the word 'duplicate'; I have tried various ways and have yet to find a way that works.