180255domain: NAppears in sequencesa(n) = T(0,n) + T(1,n-1) + ... + T(n,0), array T given by A048472.at n=13A048481Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 0 3 5 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 0 3 5 6 or 7.at n=21A252247