a(n) = ceiling((2^n+n-1)/n).

Terms

a(0) =2a(1) =3a(2) =4a(3) =5a(4) =8a(5) =12a(6) =20a(7) =33a(8) =58a(9) =104a(10) =188a(11) =343a(12) =632a(13) =1172a(14) =2186a(15) =4097a(16) =7712a(17) =14565a(18) =27596a(19) =52430a(20) =99866a(21) =190652a(22) =364724a(23) =699052a(24) =1342179a(25) =2581112a(26) =4971028a(27) =9586982a(28) =18512792a(29) =35791396