Number of unlabeled unrooted trees on 2n vertices with all vertices of odd degree.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =7a(5) =13a(6) =32a(7) =74a(8) =192a(9) =497a(10) =1379a(11) =3844a(12) =11111a(13) =32500a(14) =96977a(15) =292600a(16) =894353a(17) =2758968a(18) =8590147a(19) =26947946a(20) =85138589a(21) =270646644a(22) =865260519a(23) =2780393959a(24) =8976443582a(25) =29104709339a(26) =94741504408a(27) =309529405055