G.f. satisfies: A(x) = A(2*x^2 + x^3)/(1-x).

Terms

a(0) =1a(1) =1a(2) =3a(3) =4a(4) =16a(5) =28a(6) =63a(7) =111a(8) =391a(9) =907a(10) =2187a(11) =4555a(12) =10843a(13) =24059a(14) =53667a(15) =113503a(16) =291971a(17) =755271a(18) =1951470a(19) =4751194a(20) =11609612a(21) =27858363a(22) =66082059a(23) =152816667a(24) =355501570a(25) =832148914a(26) =1961821400a(27) =4601053219a(28) =10765373983a(29) =25089663963