T(2n-1,n-2), T given by A026659.

Terms

a(0) =1a(1) =7a(2) =28a(3) =153a(4) =560a(5) =2966a(6) =10673a(7) =56210a(8) =201515a(9) =1061236a(10) =3803919a(11) =20060748a(12) =71971953a(13) =380215935a(14) =1365763452a(15) =7227382849a(16) =25993733480a(17) =137769744017a(18) =496083782822