Number of different values of 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) =15a(5) =28a(6) =51a(7) =92a(8) =164a(9) =286a(10) =486a(11) =808a(12) =1322a(13) =2142a(14) =3456a(15) =5571a(16) =8975a(17) =14427a(18) =23094a(19) =36766a(20) =58201a(21) =91675a(22) =143841a(23) =225045a(24) =351321a(25) =547393a(26) =851160a(27) =1320339a(28) =2042195a(29) =3147614