a(n) = 2*(n-1) + Fibonacci(n).

Terms

a(0) =1a(1) =3a(2) =6a(3) =9a(4) =13a(5) =18a(6) =25a(7) =35a(8) =50a(9) =73a(10) =109a(11) =166a(12) =257a(13) =403a(14) =638a(15) =1017a(16) =1629a(17) =2618a(18) =4217a(19) =6803a(20) =10986a(21) =17753a(22) =28701a(23) =46414a(24) =75073a(25) =121443a(26) =196470a(27) =317865a(28) =514285a(29) =832098