Number of oriented rooted trees with n nodes. Also rooted trees with n nodes and 2-colored non-root nodes.

A000151

Number of oriented rooted trees with n nodes. Also rooted trees with n nodes and 2-colored non-root nodes.

Terms

    a(0) =1a(1) =2a(2) =7a(3) =26a(4) =107a(5) =458a(6) =2058a(7) =9498a(8) =44947a(9) =216598a(10) =1059952a(11) =5251806a(12) =26297238a(13) =132856766a(14) =676398395a(15) =3466799104a(16) =17873508798a(17) =92630098886a(18) =482292684506

External references