T(n,n+3), array T given by A047000.

Terms

a(0) =1a(1) =4a(2) =14a(3) =50a(4) =180a(5) =658a(6) =2429a(7) =9052a(8) =33975a(9) =128320a(10) =487124a(11) =1857362a(12) =7108400a(13) =27293280a(14) =105090130a(15) =405643176a(16) =1569193041a(17) =6082113750a(18) =23615073305a(19) =91834287660a(20) =357631419474