Number of nX4 binary arrays with each sum of a(1..i,1..j) no greater than i*j/2 and rows and columns in nondecreasing order.

A183411

Number of nX4 binary arrays with each sum of a(1..i,1..j) no greater than i*j/2 and rows and columns in nondecreasing order.

Terms

    a(0) =3a(1) =15a(2) =75a(3) =380a(4) =1518a(5) =6450a(6) =20066a(7) =69431a(8) =178672a(9) =525241a(10) =1180351a(11) =3058649a(12) =6214736a(13) =14582583a(14) =27430148a(15) =59415592a(16) =105109158a(17) =213169589a(18) =358764046a(19) =688540612a(20) =1111600419a(21) =2035522230a(22) =3172787043a(23) =5579376657a(24) =8437795792a(25) =14323523879

External references