T(n,n+2), array T as in A047100.

Terms

a(0) =1a(1) =3a(2) =10a(3) =36a(4) =130a(5) =476a(6) =1769a(7) =6630a(8) =25017a(9) =94961a(10) =362181a(11) =1386826a(12) =5328341a(13) =20531796a(14) =79315343a(15) =307077270a(16) =1191203283a(17) =4628896233a(18) =18015359847a(19) =70212552034a(20) =273990076816