Number of binary strings of length n with no substrings equal to 0001 1011 or 1100.

Terms

a(0) =13a(1) =20a(2) =30a(3) =45a(4) =68a(5) =103a(6) =156a(7) =236a(8) =356a(9) =536a(10) =806a(11) =1211a(12) =1819a(13) =2732a(14) =4103a(15) =6162a(16) =9254a(17) =13897a(18) =20869a(19) =31338a(20) =47058a(21) =70663a(22) =106108a(23) =159332a(24) =239253a(25) =359262a(26) =539467a(27) =810062a(28) =1216386a(29) =1826520