567540domain: NAppears in sequencesTriangle read by rows: numbers of isomers of unbranched a-4-catapolynonagons.at n=59A120650Unbranched a-4-catapolynonagons (see Brunvoll reference for precise definition).at n=6A121127Number of labeled digraphs without isolated vertices and with n arcs.at n=5A121252