a(n) = n + Fibonacci(n+1).

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =9a(5) =13a(6) =19a(7) =28a(8) =42a(9) =64a(10) =99a(11) =155a(12) =245a(13) =390a(14) =624a(15) =1002a(16) =1613a(17) =2601a(18) =4199a(19) =6784a(20) =10966a(21) =17732a(22) =28679a(23) =46391a(24) =75049a(25) =121418a(26) =196444a(27) =317838a(28) =514257a(29) =832069