a(n) = ceiling(2^n/n).

Terms

a(0) =2a(1) =2a(2) =3a(3) =4a(4) =7a(5) =11a(6) =19a(7) =32a(8) =57a(9) =103a(10) =187a(11) =342a(12) =631a(13) =1171a(14) =2185a(15) =4096a(16) =7711a(17) =14564a(18) =27595a(19) =52429a(20) =99865a(21) =190651a(22) =364723a(23) =699051a(24) =1342178a(25) =2581111a(26) =4971027a(27) =9586981a(28) =18512791a(29) =35791395