a(n) = floor((2^n)/(2n-1)).

Terms

a(0) =2a(1) =1a(2) =1a(3) =2a(4) =3a(5) =5a(6) =9a(7) =17a(8) =30a(9) =53a(10) =97a(11) =178a(12) =327a(13) =606a(14) =1129a(15) =2114a(16) =3971a(17) =7489a(18) =14169a(19) =26886a(20) =51150a(21) =97541a(22) =186413a(23) =356962a(24) =684784a(25) =1315860a(26) =2532409a(27) =4880644a(28) =9418787a(29) =18199013