Number of binary strings of length n with no substrings equal to 0001 0010 or 1011.

Terms

a(0) =13a(1) =21a(2) =33a(3) =51a(4) =78a(5) =119a(6) =181a(7) =275a(8) =417a(9) =632a(10) =957a(11) =1449a(12) =2193a(13) =3319a(14) =5022a(15) =7599a(16) =11497a(17) =17395a(18) =26317a(19) =39816a(20) =60237a(21) =91133a(22) =137873a(23) =208587a(24) =315566a(25) =477415a(26) =722269a(27) =1092707a(28) =1653129a(29) =2500984