Number of binary sequences of length n with no subsequence 0101.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =15a(5) =28a(6) =53a(7) =100a(8) =188a(9) =354a(10) =667a(11) =1256a(12) =2365a(13) =4454a(14) =8388a(15) =15796a(16) =29747a(17) =56020a(18) =105497a(19) =198672a(20) =374140a(21) =704582a(22) =1326871a(23) =2498768a(24) =4705689a(25) =8861770a(26) =16688516a(27) =31427872a(28) =59185079a(29) =111457548