Reversion of rooted trees A000081.

Terms

a(0) =1a(1) =-1a(2) =0a(3) =1a(4) =-1a(5) =1a(6) =-4a(7) =11a(8) =-18a(9) =18a(10) =0a(11) =-60a(12) =189a(13) =-360a(14) =453a(15) =-373a(16) =294a(17) =-652a(18) =1443a(19) =-841a(20) =-6127a(21) =27681a(22) =-75150a(23) =172371a(24) =-389662a(25) =867415a(26) =-1630604a(27) =1826409a(28) =1738343a(29) =-15855044