Number of binary strings of length n with no substrings equal to 0000, 0111 or 1110.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =13a(5) =22a(6) =37a(7) =64a(8) =110a(9) =190a(10) =329a(11) =570a(12) =988a(13) =1713a(14) =2971a(15) =5153a(16) =8938a(17) =15504a(18) =26894a(19) =46652a(20) =80926a(21) =140381a(22) =243517a(23) =422426a(24) =732778a(25) =1271143a(26) =2205040a(27) =3825063a(28) =6635303a(29) =11510202