8707375104domain: NAppears in sequencesa(n) = 4^n*(n^3 - 3*n^2 + 2*n + 384)/384.at n=15A081915Number of (n+2) X (7+2) 0..3 arrays with every 3 X 3 subblock row and column sum equal to 0 2 3 6 or 7 and every 3 X 3 diagonal and antidiagonal sum not equal to 0 2 3 6 or 7.at n=24A252113