a(n) = 2*(A000045(n)-(n mod 2)) + 1 + (n mod 2).

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =7a(5) =10a(6) =17a(7) =26a(8) =43a(9) =68a(10) =111a(11) =178a(12) =289a(13) =466a(14) =755a(15) =1220a(16) =1975a(17) =3194a(18) =5169a(19) =8362a(20) =13531a(21) =21892a(22) =35423a(23) =57314a(24) =92737a(25) =150050a(26) =242787a(27) =392836a(28) =635623a(29) =1028458