Number of rooted trees with n nodes and omega-valency 2.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =1a(5) =5a(6) =9a(7) =29a(8) =62a(9) =181a(10) =422a(11) =1166a(12) =2885a(13) =7788a(14) =19893a(15) =53319a(16) =138931a(17) =372027a(18) =982379a(19) =2635898a(20) =7026483a(21) =18914903a(22) =50781803a(23) =137201419a(24) =370442111a(25) =1004512375a(26) =2724867782a(27) =7414635185a(28) =20193165834a(29) =55125632502