a(n) = A259095(2n,n).

Terms

a(0) =0a(1) =0a(2) =1a(3) =2a(4) =5a(5) =11a(6) =20a(7) =37a(8) =63a(9) =110a(10) =174a(11) =283a(12) =435a(13) =671a(14) =1001a(15) =1492a(16) =2160a(17) =3127a(18) =4442a(19) =6269a(20) =8739a(21) =12109a(22) =16597a(23) =22618a(24) =30576a(25) =41077a(26) =54834a(27) =72788a(28) =96056a(29) =126131