a(n) = floor(4^n/((1+sqrt(5))/2)^(2*n)).

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =5a(5) =8a(6) =12a(7) =19a(8) =29a(9) =45a(10) =69a(11) =105a(12) =161a(13) =247a(14) =377a(15) =577a(16) =881a(17) =1347a(18) =2058a(19) =3144a(20) =4805a(21) =7341a(22) =11216a(23) =17137a(24) =26183a(25) =40005a(26) =61122a(27) =93387a(28) =142682a(29) =218000