Fifteen Oscar statuettes are to be auctioned off next week in what organisers said on Tuesday is the largest collection of Academy Awards ever to go under the hammer. Los Angeles auctioneers Nate D. Sanders said the Oscars that will go up for grabs two days after the 2012 Academy Awards ceremony include the one given to writer Herman Mankiewicz for his “Citizen Kane” screenplay with Orson Welles.