a(n) = k if k is odd otherwise a(n) = k+1 and k = floor( 2^n*(1+sqrt(5))/2 ).

Terms

a(0) =1a(1) =3a(2) =7a(3) =13a(4) =25a(5) =51a(6) =103a(7) =207a(8) =415a(9) =829a(10) =1657a(11) =3313a(12) =6627a(13) =13255a(14) =26509a(15) =53019a(16) =106039a(17) =212079a(18) =424157a(19) =848315a(20) =1696631a(21) =3393263a(22) =6786527a(23) =13573053a(24) =27146105a(25) =54292211a(26) =108584423a(27) =217168845a(28) =434337691a(29) =868675383