Generalized tangent numbers d_(n,3).

Terms

a(0) =16a(1) =361a(2) =3362a(3) =16384a(4) =55744a(5) =152166a(6) =355688a(7) =739328a(8) =1415232a(9) =2529614a(10) =4261454a(11) =6885376a(12) =10708160a(13) =16054580a(14) =23494584a(15) =33554432a(16) =46698624a(17) =64037790a(18) =86342918a(19) =114163712a(20) =149518720a(21) =193356526a(22) =246232840a(23) =311635968a(24) =390600000