A038015 - OEIS

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A038015

Number of pointed (distinguished element) idempotent groupoids.

1, 4, 378, 2798336, 3973658465625, 1842282678468471349824, 433296503176904197061300041939288, 74235003800935257803650942510752495927455127552 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	LINKS	`Index entries for sequences related to groupoids`
	FORMULA	`fix F[ n ]=n(1)prod{i, j >= 1}(sum{d\|[ i, j ]}(dn(d))^((i, j)n(i)n(j)-(i=j)n(i)))`
	CROSSREFS	`Cf. A001329, A030247.` `Sequence in context: A051181 A154682 A154569 * A003753 A193130 A006237` `Adjacent sequences: A038012 A038013 A038014 * A038016 A038017 A038018`
	KEYWORD	`nonn`
	AUTHOR	`Christian G. Bower (bowerc(AT)usa.net), May 15 1998.`

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Last modified February 15 05:29 EST 2012. Contains 205694 sequences.