A000016 / 2.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =5a(5) =8a(6) =15a(7) =26a(8) =47a(9) =86a(10) =158a(11) =293a(12) =548a(13) =1024a(14) =1928a(15) =3643a(16) =6899a(17) =13108a(18) =24970a(19) =47663a(20) =91181a(21) =174768a(22) =335546a(23) =645278a(24) =1242767a(25) =2396746a(26) =4628198a(27) =8947868a(28) =17318417a(29) =33554432