Twice the total area of all (open or closed) Deutsch paths of length n.

Terms

a(0) =0a(1) =1a(2) =6a(3) =25a(4) =90a(5) =306a(6) =1004a(7) =3226a(8) =10218a(9) =32043a(10) =99748a(11) =308787a(12) =951772a(13) =2923563a(14) =8955342a(15) =27368895a(16) =83484042a(17) =254244033a(18) =773219196a(19) =2348780937a(20) =7127522136a(21) =21609615822a(22) =65465845254a(23) =198189732798a(24) =599624708588