Number of asymmetric planar trees with n nodes.

Terms

a(0) =1a(1) =1a(2) =0a(3) =0a(4) =0a(5) =1a(6) =3a(7) =9a(8) =28a(9) =85a(10) =262a(11) =827a(12) =2651a(13) =8626a(14) =28507a(15) =95393a(16) =322938a(17) =1104525a(18) =3812367a(19) =13266366a(20) =46504495a(21) =164098390a(22) =582521687a(23) =2079133141a(24) =7457788295a(25) =26872946466a(26) =97238824018a(27) =353218128299