Number of n-node rooted identity trees with thinning limbs and root outdegree (branching factor) 3.

Terms

a(0) =1a(1) =2a(2) =4a(3) =9a(4) =17a(5) =35a(6) =67a(7) =131a(8) =249a(9) =484a(10) =922a(11) =1775a(12) =3393a(13) =6513a(14) =12461a(15) =23910a(16) =45806a(17) =87903a(18) =168619a(19) =323796a(20) =621816a(21) =1195123a(22) =2297617a(23) =4420093a(24) =8506487a(25) =16380013a(26) =31554394a(27) =60817066a(28) =117266799a(29) =226217218