Number of cyclic binary n-bit strings with no alternating substring of length > 2.

Terms

a(0) =2a(1) =2a(2) =2a(3) =6a(4) =12a(5) =20a(6) =30a(7) =46a(8) =74a(9) =122a(10) =200a(11) =324a(12) =522a(13) =842a(14) =1362a(15) =2206a(16) =3572a(17) =5780a(18) =9350a(19) =15126a(20) =24474a(21) =39602a(22) =64080a(23) =103684a(24) =167762a(25) =271442a(26) =439202a(27) =710646a(28) =1149852a(29) =1860500