Number of ternary length-2 squarefree words of length n not containing the subwords 021 or 10.

Terms

a(0) =1a(1) =3a(2) =5a(3) =7a(4) =11a(5) =16a(6) =24a(7) =36a(8) =53a(9) =80a(10) =118a(11) =177a(12) =263a(13) =392a(14) =585a(15) =870a(16) =1299a(17) =1933a(18) =2883a(19) =4295a(20) =6400a(21) =9540a(22) =14212a(23) =21185a(24) =31564a(25) =47042a(26) =70101a(27) =104463a(28) =155680a(29) =231985