T(n,n+3), array T given by A047020.

Terms

a(0) =1a(1) =4a(2) =14a(3) =48a(4) =170a(5) =611a(6) =2214a(7) =8135a(8) =30171a(9) =112589a(10) =423114a(11) =1598998a(12) =6068246a(13) =23125097a(14) =88441638a(15) =339234219a(16) =1304756453a(17) =5030574435a(18) =19436510637a(19) =75241443220a(20) =291780678294