T(n,2), array T as in A054126.

Terms

a(0) =2a(1) =7a(2) =24a(3) =68a(4) =171a(5) =398a(6) =880a(7) =1880a(8) =3925a(9) =8070a(10) =16426a(11) =33216a(12) =66887a(13) =134334a(14) =269348a(15) =539512a(16) =1079993a(17) =2161126a(18) =4323582a(19) =8648704a(20) =17299179a(21) =34600382a(22) =69203064a(23) =138408728a(24) =276820381a(25) =553644038a(26) =1107291730a(27) =2214587520