Duplicate of A001519.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =13a(5) =34a(6) =89a(7) =233a(8) =610a(9) =1597a(10) =4181a(11) =10946a(12) =28657a(13) =75025a(14) =196418a(15) =514229