Number of binary necklaces with n beads and at least two consecutive black beads.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =5a(5) =9a(6) =15a(7) =28a(8) =50a(9) =93a(10) =169a(11) =321a(12) =591a(13) =1118a(14) =2098a(15) =3973a(16) =7501a(17) =14273a(18) =27103a(19) =51722a(20) =98710a(21) =188935a(22) =361937a(23) =694911a(24) =1335471a(25) =2570966a(26) =4954794a(27) =9562165a(28) =18473141a(29) =35730493