A007903 - OEIS

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A007903

Principal ideals in semigroup of binary relations on an n-set.

2, 4, 11, 60, 877, 42944, 7339704 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	REFERENCES	`Jin Bai Kim, Bull. Korean Math. Soc., 1983` `George Markowsky, 1991; Markowsky and Breen, 1993; Breen, 1995.`
	LINKS	`Index entries for sequences related to semigroups`
	CROSSREFS	`Sequence in context: A091233 A173312 A156434 * A006894 A193565 A198864` `Adjacent sequences: A007900 A007901 A007902 * A007904 A007905 A007906`
	KEYWORD	`nonn,hard,nice`
	AUTHOR	`Michael A Breen [ MAB1699(AT)tntech.edu ]`

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Last modified February 17 06:22 EST 2012. Contains 205992 sequences.