a(n) = A143565(2n,n) for n > 0, a(0) = 1.

Terms

a(0) =1a(1) =3a(2) =13a(3) =61a(4) =281a(5) =1261a(6) =5545a(7) =24025a(8) =102961a(9) =437581a(10) =1847561a(11) =7759753a(12) =32449873a(13) =135207801a(14) =561632401a(15) =2326762801a(16) =9617286241a(17) =39671305741a(18) =163352435401a(19) =671560012201