a(n) = A097609(2*n-1,n), n>0; a(0)=1.

Terms

a(0) =1a(1) =0a(2) =2a(3) =3a(4) =18a(5) =50a(6) =215a(7) =735a(8) =2898a(9) =10668a(10) =41202a(11) =156090a(12) =601623a(13) =2308878a(14) =8923343a(15) =34487453a(16) =133749330a(17) =519277512a(18) =2020262660a(19) =7869597840a(20) =30699524018a(21) =119894389380a(22) =468768069882