Number of (n+1)X(3+1) 0..1 arrays with every 2X2 subblock sum nondecreasing horizontally, vertically and antidiagonally ne-to-sw.

A253321

Number of (n+1)X(3+1) 0..1 arrays with every 2X2 subblock sum nondecreasing horizontally, vertically and antidiagonally ne-to-sw.

Terms

    a(0) =121a(1) =373a(2) =1217a(3) =2538a(4) =6190a(5) =11795a(6) =25659a(7) =48085a(8) =99653a(9) =188562a(10) =382854a(11) =736066a(12) =1481812a(13) =2889153a(14) =5795537a(15) =11413655a(16) =22859675a(17) =45310136a(18) =90683516a(19) =180442820a(20) =361012010a(21) =719966855a(22) =1440188551a(23) =2875847161a(24) =5752209057a(25) =11494526782

External references