T(2n+1,n+3), T given by A026769.

Terms

a(0) =1a(1) =7a(2) =37a(3) =178a(4) =825a(5) =3774a(6) =17250a(7) =79326a(8) =368516a(9) =1733597a(10) =8268603a(11) =40003178a(12) =196273837a(13) =976066486a(14) =4915503146a(15) =25042730042a(16) =128927697340a(17) =670023585820