a(n) is the number of binary strings of length n such that no subsequence of length 5 or less contains 4 or more ones.

A125513

a(n) is the number of binary strings of length n such that no subsequence of length 5 or less contains 4 or more ones.

Terms

    a(0) =2a(1) =4a(2) =8a(3) =15a(4) =26a(5) =48a(6) =89a(7) =165a(8) =305a(9) =561a(10) =1034a(11) =1908a(12) =3521a(13) =6496a(14) =11982a(15) =22101a(16) =40770a(17) =75210a(18) =138741a(19) =255934a(20) =472117a(21) =870911a(22) =1606567a(23) =2963628a(24) =5466988a(25) =10084919a(26) =18603592a(27) =34317946a(28) =63306130a(29) =116780470

External references