Number of rooted asymmetrical polyenoids of type U_n* having n edges.

Terms

a(0) =0a(1) =2a(2) =4a(3) =10a(4) =28a(5) =84a(6) =264a(7) =858a(8) =2860a(9) =9724a(10) =33592a(11) =117572a(12) =416024a(13) =1485800a(14) =5348880a(15) =19389690a(16) =70715340a(17) =259289580a(18) =955277400a(19) =3534526380a(20) =13128240840a(21) =48932534040a(22) =182965127280a(23) =686119227300