T(2n,n) with T(n,m) as in A063394.

Terms

a(0) =1a(1) =3a(2) =19a(3) =131a(4) =979a(5) =7683a(6) =62099a(7) =511619a(8) =4271699a(9) =36018179a(10) =305998099a(11) =2615234691a(12) =22459983059a(13) =193665818115