Number of binary sequences of length n containing exactly one subsequence 0000.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =2a(6) =5a(7) =12a(8) =28a(9) =62a(10) =136a(11) =294a(12) =628a(13) =1328a(14) =2787a(15) =5810a(16) =12043a(17) =24840a(18) =51016a(19) =104380a(20) =212848a(21) =432732a(22) =877400a(23) =1774672a(24) =3581605a(25) =7213746a(26) =14502449a(27) =29106100a(28) =58323844a(29) =116702074