A051504 Number of asymmetric digraphs with n nodes.

1, 1, 1, 7, 136, 8001, 1445297, 863488287

Offset: 0

Author

Vladeta Jovovic

Keywords

• hard
• nonn
• nice

References

• F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 231.
• P. K. Stockmeyer, The enumeration of graphs with prescribed automorphism group, Dissertation, Univ. of Michigan, Ann Arbor, 1971.

Crossrefs

Cf. A000273 (digraphs), A003400 (asymmetric graphs), A030242 (asymmetric relations), A067309.

Formula

a(n) = A000273(n) - A067309(n). - Andrew Howroyd, Dec 06 2020

Extensions

a(6) from Christian G. Bower Dec 15 1999

a(7) from Andrew Howroyd, Dec 06 2020