15344171domain: NPropertiesPrimalityPrimeyesAppears in sequencesNumber of (n+2)X(n+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 3 5 6 or 7 and every 3X3 diagonal and antidiagonal sum not equal to 0 3 5 6 or 7.at n=13A252140Prime numbersat n=991513