T(n,n-3), array T given by A047000.

Terms

a(0) =1a(1) =2a(2) =3a(3) =14a(4) =30a(5) =143a(6) =728a(7) =3148a(8) =13566a(9) =56221a(10) =231308a(11) =939090a(12) =3793530a(13) =15237792a(14) =61020524a(15) =243678476a(16) =971345694a(17) =3866131073a(18) =15371516800a(19) =61064462784a(20) =242432019936a(21) =962016777729