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

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =4a(6) =7a(7) =11a(8) =16a(9) =26a(10) =41a(11) =62a(12) =99a(13) =156a(14) =240a(15) =379a(16) =596a(17) =925a(18) =1453a(19) =2281a(20) =3556a(21) =5575a(22) =8742a(23) =13658a(24) =21394a(25) =33524a(26) =52432a(27) =82100a(28) =128597a(29) =201233