Essentially the same as A001611.

Terms

a(0) =2a(1) =3a(2) =4a(3) =6a(4) =9a(5) =14a(6) =22a(7) =35a(8) =56a(9) =90a(10) =145a(11) =234a(12) =378a(13) =611a(14) =988a(15) =1598a(16) =2585a(17) =4182a(18) =6766