T(n,4), array T as in A054126.

Terms

a(0) =2a(1) =11a(2) =58a(3) =236a(4) =802a(5) =2396a(6) =6508a(7) =16448a(8) =39331a(9) =90102a(10) =199652a(11) =431128a(12) =912644a(13) =1902808a(14) =3921896a(15) =8014336a(16) =16273829a(17) =32893762a(18) =66268224a(19) =133194248a(20) =267276526a(21) =535737092a(22) =1073034964a(23) =2148105728a(24) =4298841031a(25) =8601047918a(26) =17206367884a(27) =34418115384a(28) =68842955288