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A038015 Number of pointed (distinguished element) idempotent groupoids. 3
1, 4, 378, 2798336, 3973658465625, 1842282678468471349824, 433296503176904197061300041939288, 74235003800935257803650942510752495927455127552 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..8.

Index entries for sequences related to groupoids

FORMULA

fix F[n] = n(1)*Product_{i, j >= 1}(Sum_{d|[i, j]}(d*n(d))^((i, j)*n(i)*n(j)-(i=j)n(i))).

CROSSREFS

Cf. A001329, A030247.

Sequence in context: A154682 A292195 A154569 * A279525 A003753 A193130

Adjacent sequences:  A038012 A038013 A038014 * A038016 A038017 A038018

KEYWORD

nonn

AUTHOR

Christian G. Bower, May 15 1998

STATUS

approved

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Last modified October 20 05:42 EDT 2017. Contains 293601 sequences.