T(n,n+3), array T given by A047010.

Terms

a(0) =1a(1) =4a(2) =15a(3) =55a(4) =203a(5) =756a(6) =2835a(7) =10698a(8) =40590a(9) =154711a(10) =591998a(11) =2272920a(12) =8752198a(13) =33787677a(14) =130729863a(15) =506821408a(16) =1968360249a(17) =7656736914a(18) =29826609906a(19) =116339203127a(20) =454317156153