Number of different values of (x_n, x_1*x_2*...*x_n) where x_1=1 and x_i-x_{i-1} is 0 or 1.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =16a(5) =31a(6) =59a(7) =110a(8) =202a(9) =366a(10) =653a(11) =1143a(12) =1961a(13) =3303a(14) =5480a(15) =8992a(16) =14647a(17) =23742a(18) =38334a(19) =61648a(20) =98700a(21) =157265a(22) =249397a(23) =393814a(24) =619611a(25) =971988a(26) =1521015a(27) =2374946a(28) =3700290a(29) =5751806