A trisection of A121653; a(n) = A121653(3*n+2) = A121652(3*n+2)^(1/3).

Terms

a(0) =1a(1) =3a(2) =9a(3) =28a(4) =102a(5) =378a(6) =1390a(7) =5229a(8) =19785a(9) =74761a(10) =283143a(11) =1073820a(12) =4072442a(13) =15617469a(14) =59967564a(15) =230081349a(16) =889342557a(17) =3443431566a(18) =13326462430a(19) =51756384099a(20) =201245258853a(21) =782441280159