OFFSET
1,4
COMMENTS
Also, number of directed graphs on n labeled nodes that do not contain a subgraph isomorphic to the complete directed bipartite graph K_{2,2} and have largest number of edges (=A191873(n)). - Max Alekseyev, Feb 07 2022
CROSSREFS
KEYWORD
nonn,more
AUTHOR
R. H. Hardin and N. J. A. Sloane, Jun 18 2011
EXTENSIONS
a(8)-a(12) from Max Alekseyev, Feb 07 2022
STATUS
approved