Number of binary strings of length n with no substrings equal to 0000 0001 or 1111.

Terms

a(0) =13a(1) =23a(2) =40a(3) =69a(4) =120a(5) =208a(6) =361a(7) =626a(8) =1086a(9) =1884a(10) =3268a(11) =5669a(12) =9834a(13) =17059a(14) =29592a(15) =51333a(16) =89047a(17) =154469a(18) =267956a(19) =464821a(20) =806321a(21) =1398718a(22) =2426344a(23) =4208958a(24) =7301243a(25) =12665403a(26) =21970565a(27) =38112149a(28) =66112815a(29) =114685328