Triangle read by rows: T(n,k) is number of noncrossing trees with n edges and having k nonroot branch nodes.

A101431

Triangle read by rows: T(n,k) is number of noncrossing trees with n edges and having k nonroot branch nodes.

Terms

    a(0) =1a(1) =3a(2) =9a(3) =3a(4) =27a(5) =28a(6) =81a(7) =174a(8) =18a(9) =243a(10) =900a(11) =285a(12) =729a(13) =4185a(14) =2703a(15) =135a(16) =2187a(17) =18144a(18) =19908a(19) =3024a(20) =6561a(21) =74844a(22) =125496a(23) =38640a(24) =1134a(25) =19683a(26) =297432a(27) =711018a(28) =369696a(29) =32886

External references