id:A007868 - OEIS Search Results

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Number of inverse pairs of elements in symmetric group S_n, or pairs of total orders on n nodes (average of A000085 and A000142).

+0
1

1, 1, 2, 5, 17, 73, 398, 2636, 20542, 182750, 1819148, 19976248, 239570876, 3113794652, 43590340840, 653842358768, 10461418047368, 177843819947656 (list; graph; listen)

	OFFSET	`0,3`
	LINKS	`T. D. Noe, Table of n, a(n) for n=0..100` `P. J. Cameron, Sequences realized by oligomorphic permutation groups, J. Integ. Seqs. Vol. 3 (2000), #00.1.5.`
	CROSSREFS	`Sequence in context: A084161 A102038 A002135 this_sequence A136726 A112831 A000774` `Adjacent sequences: A007865 A007866 A007867 this_sequence A007869 A007870 A007871`
	KEYWORD	`nonn,nice`
	AUTHOR	`Peter Cameron [ P.J.Cameron(AT)qmw.ac.uk ]`

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Last modified November 25 08:46 EST 2009. Contains 167481 sequences.

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