A067309 - OEIS

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A067309

Number of symmetric unlabeled digraphs (unlabeled digraphs with nontrivial automorphism group).

0, 0, 2, 9, 82, 1607, 95647 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,3`
	FORMULA	`a(n)=A000273(n)-A051504(4)`
	EXAMPLE	`For n=4 nodes from the 218 (=A000273(4)) unlabeled nonisomorphic digraphs 136(=A051504(4)) are asymmetric, so 218-136=82 are somehow symmetric.`
	CROSSREFS	`Cf. A000273, A051504.` `Sequence in context: A117581 A123570 A006040 * A087798 A113146 A069234` `Adjacent sequences: A067306 A067307 A067308 * A067310 A067311 A067312`
	KEYWORD	`nonn`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu), Jan 11 2002`

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Last modified February 14 08:46 EST 2012. Contains 205614 sequences.