Twice the area of the convex hull around dragon curve expansion level n.

Terms

a(0) =0a(1) =1a(2) =3a(3) =9a(4) =23a(5) =56a(6) =121a(7) =258a(8) =539a(9) =1118a(10) =2273a(11) =4614a(12) =9323a(13) =18806a(14) =37761a(15) =75798a(16) =151979a(17) =304598a(18) =609793a(19) =1220694a(20) =2442923a(21) =4888406a(22) =9779201a(23) =19562838a(24) =39131819a(25) =78273878a(26) =156557313a(27) =313132374a(28) =626289323a(29) =1252619606