A003030 - OEIS

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A003030

Number of strongly connected digraphs with n labeled nodes.
(Formerly M5064)

1, 1, 18, 1606, 565080, 734774776, 3523091615568, 63519209389664176, 4400410978376102609280, 1190433705317814685295399296, 1270463864957828799318424676767488 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,3`
	COMMENTS	`As usual, there can be an edge both from i to j and from j to i.`
	REFERENCES	`R. C. Read and R. J. Wilson, An Atlas of Graphs, Oxford, 1998.` `R. W. Robinson, Counting labeled acyclic digraphs, pp. 239-273 of F. Harary, editor, New Directions in the Theory of Graphs. Academic Press, NY, 1973.` `R. W. Robinson, personal communication.` `R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1980.` `N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).`
	LINKS	`R. W. Robinson, Table of n, a(n) for n = 1..18` `Huantian Cao, AutoGF: An Automated System to Calculate Coefficients of Generating Functions.`
	EXAMPLE	`a(3) = 18 (the symbol = denotes a pair of parallel edges): 1->2->3->1 (2 such); 1=2->3->1 (6); 1=2=3->1 (6); 1=2=3=1 (1); 1=2=3 (3).`
	CROSSREFS	`Cf. A035512, A054946 (strongly connected labeled tournaments).` `Sequence in context: A177602 A160252 A160307 * A086366 A086193 A064347` `Adjacent sequences: A003027 A003028 A003029 * A003031 A003032 A003033`
	KEYWORD	`nonn,nice`
	AUTHOR	`N. J. A. Sloane (njas(AT)research.att.com).`

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Last modified February 17 12:36 EST 2012. Contains 206020 sequences.