Sum over each antidiagonal of A248017.

Terms

a(0) =0a(1) =0a(2) =0a(3) =4a(4) =69a(5) =554a(6) =3100a(7) =13288a(8) =47492a(9) =147050a(10) =407568a(11) =1030912a(12) =2419025a(13) =5324684a(14) =11099416a(15) =22065120a(16) =42085344a(17) =77378556a(18) =137705904a(19) =237996060a(20) =400624581a(21) =658434694a(22) =1058839380a(23) =1669118984a(24) =2583424948a(25) =3931632406a(26) =5890783808a(27) =8699293304a(28) =12674960961