Number of unlabeled binary rooted semi-identity plane trees with 2*n - 1 nodes.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =12a(5) =34a(6) =108a(7) =344a(8) =1136a(9) =3796a(10) =12920a(11) =44442a(12) =154596a(13) =542336a(14) =1917648a(15) =6825464a(16) =24439008a(17) =87962312a(18) =318087216a(19) =1155090092a(20) =4210494616a(21) =15400782912a(22) =56508464736a(23) =207935588586a(24) =767162495940