A079174 - OEIS

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A079174

Number of isomorphism classes of non-associative closed binary operations on a set of order n, listed by class size.

0, 2, 3, 1, 12, 71, 3222, 0, 1, 14, 23, 270, 495, 48748, 178932213 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`A079174(n)+A079175(n)=A079171(n)` `Elements per row: 1,2,4,8,16,30,60,96 (A027423, number of positive divisors of n!)` `First four rows: 0; 2,3; 1,12,71,3222; 0,1,14,23,270,495,48748,178932213` `The sum of each row n is given by A079173(n).`
	LINKS	`C. van den Bosch, Closed binary operations on small sets` `Index entries for sequences related to groupoids`
	CROSSREFS	`Cf. A079172, A079173, A079175.` `Sequence in context: A142714 A176701 A107415 * A204137 A102583 A030780` `Adjacent sequences: A079171 A079172 A079173 * A079175 A079176 A079177`
	KEYWORD	`nonn,tabf`
	AUTHOR	`Christian van den Bosch (cjb(AT)cjb.ie), Jan 03 2003`

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Last modified February 14 20:38 EST 2012. Contains 205663 sequences.