id:A090751 - OEIS Search Results

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Number of indecomposable groups of order n.

+0
4

0, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 2, 1, 1, 0, 8, 1, 2, 1, 2, 1, 1, 1, 6, 1, 1, 3, 1, 1, 1, 1, 34, 0, 1, 0, 4, 1, 1, 1, 5, 1, 2, 1, 1, 0, 1, 1, 23, 1, 2, 0, 2, 1, 6, 1, 5, 1, 1, 1, 3, 1, 1, 1, 201, 0, 1, 1, 2, 0, 1, 1, 19, 1, 1, 1, 1, 0, 2, 1, 24, 9, 1, 1, 3, 0, 1, 0, 4, 1, 2, 0, 1, 1, 1, 0, 121, 1, 2, 0, 6, 1 (list; graph; listen)

	OFFSET	`1,8`
	COMMENT	`Indecomposable means nontrivial and not a direct product of two proper subgroups. Any finite group G is a direct product of indecomposable groups and the multiset of isomorphism types of indecomposable factors is an invariant of G. Hence A000001 has Dirichlet generating function prod((1-n^(-s))^(-a(n)),n>=2).`
	REFERENCES	`Derek J. S. Robinson, A course in the theory of groups, Graduate texts in mathematics 80, Springer-Verlag, 1982.`
	CROSSREFS	`Sequence in context: A054724 A061494 A141901 this_sequence A030369 A023520 A082062` `Adjacent sequences: A090748 A090749 A090750 this_sequence A090752 A090753 A090754`
	KEYWORD	`nonn,nice`
	AUTHOR	`Paul Boddington (psb(AT)maths.warwick.ac.uk), Feb 03 2004`
	EXTENSIONS	`More terms from Christian G. Bower (bowerc(AT)usa.net), May 12 2005`

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Last modified December 1 13:27 EST 2009. Contains 167806 sequences.

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