Number of (marked) cyclic n-bit binary strings containing no runs of length > 3.

Terms

a(0) =2a(1) =4a(2) =8a(3) =14a(4) =20a(5) =38a(6) =70a(7) =134a(8) =240a(9) =442a(10) =814a(11) =1502a(12) =2756a(13) =5070a(14) =9326a(15) =17158a(16) =31552a(17) =58034a(18) =106742a(19) =196334a(20) =361108a(21) =664182a(22) =1221622a(23) =2246918a(24) =4132720a(25) =7601258a(26) =13980894a(27) =25714878a(28) =47297028a(29) =86992798