G.f.: (x+x^3+x^4)/(1-x-x^3-2*x^4).

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =4a(5) =7a(6) =11a(7) =19a(8) =34a(9) =59a(10) =100a(11) =172a(12) =299a(13) =517a(14) =889a(15) =1532a(16) =2647a(17) =4570a(18) =7880a(19) =13591a(20) =23455a(21) =40475a(22) =69826a(23) =120463a(24) =207848a(25) =358624a(26) =618739a(27) =1067513a(28) =1841833a(29) =3177820