156500domain: NAppears in sequencesNumber of (1+2)X(n+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 0 1 3 6 or 7 and every 3X3 column and antidiagonal sum not equal to 0 1 3 6 or 7.at n=11A252306G.f. satisfies: A(x) = 1/(1 - x/(1 - x*A(x))^4)^2.at n=7A349023