Bisection of A001523.

Terms

a(0) =1a(1) =2a(2) =8a(3) =27a(4) =79a(5) =209a(6) =512a(7) =1183a(8) =2604a(9) =5504a(10) =11240a(11) =22277a(12) =43003a(13) =81098a(14) =149769a(15) =271404a(16) =483439a(17) =847681a(18) =1464999a(19) =2498258a(20) =4207764a(21) =7005688a(22) =11538936a(23) =18814423a(24) =30387207a(25) =48641220a(26) =77205488a(27) =121567834a(28) =189974638a(29) =294742961