280654684domain: NAppears in sequencesNumber of (n+1)X(3+1) 0..3 arrays with every 2X2 subblock summing to 3 6 or 9.at n=5A251295Number of (n+1)X(6+1) 0..3 arrays with every 2X2 subblock summing to 3 6 or 9.at n=2A251298