A051504 - OEIS

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A051504

Number of asymmetric digraphs with n nodes.

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,4

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.

LINKS

Table of n, a(n) for n=0..7.

FORMULA

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

CROSSREFS

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

Sequence in context: A243684 A260535 A220380 * A058881 A100520 A221342

Adjacent sequences: A051501 A051502 A051503 * A051505 A051506 A051507

KEYWORD

hard,nonn,nice

AUTHOR

Vladeta Jovovic

EXTENSIONS

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

a(7) from Andrew Howroyd, Dec 06 2020

STATUS

approved