T(n,n+3), array T as in A047089.

Terms

a(0) =1a(1) =4a(2) =16a(3) =60a(4) =228a(5) =860a(6) =3267a(7) =12426a(8) =47471a(9) =181812a(10) =698512a(11) =2690086a(12) =10384712a(13) =40170182a(14) =155681112a(15) =604362074a(16) =2349783665a(17) =9148780570a(18) =35665860725a(19) =139202880860a(20) =543887439194