Number of asymmetric permutation rooted trees with n nodes.

Terms

a(0) =0a(1) =1a(2) =1a(3) =1a(4) =3a(5) =7a(6) =21a(7) =61a(8) =187a(9) =577a(10) =1825a(11) =5831a(12) =18883a(13) =61699a(14) =203429a(15) =675545a(16) =2258291a(17) =7592249a(18) =25656477a(19) =87096661a(20) =296891287a(21) =1015797379a(22) =3487272317a(23) =12008898531a(24) =41471260883a(25) =143588078449a(26) =498343911529