a(n) = A000045(n) + A131531(n+3).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =5a(6) =9a(7) =13a(8) =21a(9) =33a(10) =55a(11) =89a(12) =145a(13) =233a(14) =377a(15) =609a(16) =987a(17) =1597a(18) =2585a(19) =4181a(20) =6765a(21) =10945a(22) =17711a(23) =28657a(24) =46369a(25) =75025a(26) =121393a(27) =196417a(28) =317811a(29) =514229