T(n,n-2), array T as in A047060.

Terms

a(0) =1a(1) =3a(2) =9a(3) =30a(4) =103a(5) =359a(6) =1288a(7) =4689a(8) =17314a(9) =64534a(10) =242041a(11) =913736a(12) =3467291a(13) =13218109a(14) =50584796a(15) =194187685a(16) =747554181a(17) =2884909591a(18) =11157920117a(19) =43240538732a(20) =167862452804a(21) =652673851739