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

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =5a(5) =8a(6) =17a(7) =27a(8) =44a(9) =82a(10) =139a(11) =228a(12) =394a(13) =678a(14) =1136a(15) =1940a(16) =3339a(17) =5666a(18) =9647a(19) =16514a(20) =28128a(21) =47871a(22) =81714a(23) =139350a(24) =237399a(25) =404887a(26) =690570a(27) =1177098a(28) =2006935a(29) =3422404