T(2n-1,n-2), T given by A026907.

Terms

a(0) =46a(1) =239a(2) =993a(3) =3927a(4) =15327a(5) =59613a(6) =231733a(7) =901220a(8) =3507762a(9) =13666112a(10) =53295628a(11) =208049127a(12) =812931417a(13) =3179338857a(14) =12444969357a(15) =48753264432a(16) =191137360902a(17) =749893379292