Number of binary necklaces of length n with no subsequence 000.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =9a(6) =11a(7) =19a(8) =29a(9) =48a(10) =75a(11) =132a(12) =213a(13) =369a(14) =627a(15) =1083a(16) =1857a(17) =3244a(18) =5619a(19) =9844a(20) =17205a(21) =30229a(22) =53115a(23) =93701a(24) =165313a(25) =292464a(26) =517831a(27) =918578a(28) =1630933a(29) =2900109