Number of binary strings of length n with no substrings equal to 0000, 0001, or 1100.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =13a(5) =22a(6) =38a(7) =65a(8) =112a(9) =193a(10) =332a(11) =572a(12) =985a(13) =1696a(14) =2921a(15) =5030a(16) =8662a(17) =14917a(18) =25688a(19) =44237a(20) =76180a(21) =131188a(22) =225917a(23) =389048a(24) =669973a(25) =1153750a(26) =1986854a(27) =3421529a(28) =5892160a(29) =10146793