T(n,n+2), array T as in A047089.

Terms

a(0) =1a(1) =3a(2) =11a(3) =38a(4) =139a(5) =506a(6) =1881a(7) =7019a(8) =26449a(9) =100111a(10) =381060a(11) =1455872a(12) =5583063a(13) =21472978a(14) =82810941a(15) =320094718a(16) =1239852777a(17) =4811195125a(18) =18700386300a(19) =72792837115a(20) =283731854748