a(2n) = a(2n-1)+a(2n-2), a(2n+1) = a(2n)+a(2n-1)-1, a(0)=2, a(1)=1.

Terms

a(0) =2a(1) =1a(2) =3a(3) =3a(4) =6a(5) =8a(6) =14a(7) =21a(8) =35a(9) =55a(10) =90a(11) =144a(12) =234a(13) =377a(14) =611a(15) =987a(16) =1598a(17) =2584a(18) =4182a(19) =6765a(20) =10947a(21) =17711a(22) =28658a(23) =46368a(24) =75026a(25) =121393a(26) =196419a(27) =317811a(28) =514230a(29) =832040