a(n) = T(n, [n/2]), where T is the array defined in A026009.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =6a(5) =10a(6) =19a(7) =34a(8) =62a(9) =117a(10) =207a(11) =407a(12) =704a(13) =1430a(14) =2431a(15) =5070a(16) =8502a(17) =18122a(18) =30056a(19) =65246a(20) =107236a(21) =236436a(22) =385662a(23) =861764a(24) =1396652a(25) =3157325a(26) =5088865a(27) =11622015a(28) =18642420a(29) =42961470