T(n,n+1), array T as in A047150.

Terms

a(0) =1a(1) =1a(2) =6a(3) =17a(4) =68a(5) =262a(6) =898a(7) =3415a(8) =12665a(9) =48273a(10) =185597a(11) =705894a(12) =2710318a(13) =10414884a(14) =40204048a(15) =155766007a(16) =603806026a(17) =2345327257a(18) =9121945554a(19) =35535598716a(20) =138649731701a(21) =541549508686