Number of noncrossing bushes with n nodes; i.e., rooted noncrossing trees with n nodes and no nonroot nodes of degree 1.

A030981

Number of noncrossing bushes with n nodes; i.e., rooted noncrossing trees with n nodes and no nonroot nodes of degree 1.

Terms

    a(0) =1a(1) =1a(2) =4a(3) =11a(4) =41a(5) =146a(6) =564a(7) =2199a(8) =8835a(9) =35989a(10) =148912a(11) =623008a(12) =2633148a(13) =11222160a(14) =48181056a(15) =208180847a(16) =904593623a(17) =3950338043a(18) =17328256180a(19) =76316518987a(20) =337332601513

External references