a(2n) = A001906(n+1), a(2n+1) = A002878(n).

Terms

a(0) =1a(1) =1a(2) =3a(3) =4a(4) =8a(5) =11a(6) =21a(7) =29a(8) =55a(9) =76a(10) =144a(11) =199a(12) =377a(13) =521a(14) =987a(15) =1364a(16) =2584a(17) =3571a(18) =6765a(19) =9349a(20) =17711a(21) =24476a(22) =46368a(23) =64079a(24) =121393a(25) =167761a(26) =317811a(27) =439204a(28) =832040a(29) =1149851