489559domain: NAppears in sequencesNumber of n X n binary arrays with all ones connected only in a 3X3 plus 2,1 2,2 2,3 1,2 3,2.at n=9A145997Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 3 X 3 plus 2,1 2,2 2,3 1,2 3,2.at n=21A145999