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A079189 Number of anti-commutative closed binary operations (groupoids) on a set of order n. 4
1, 8, 5832, 764411904, 32000000000000000, 669462604992000000000000000, 10090701947420325348336258984797490118656, 181258495964203522486308107281962138904949048737792 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A079176(n)+A079179(n)=A002489(n).

Each a(n) is equal to the sum of the products of each element in row n of A079191 and the corresponding element of A079210.

LINKS

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

C. van den Bosch, Closed binary operations on small sets

Index entries for sequences related to groupoids

FORMULA

(n^n)((n^2-n)^((n^2-n)/2))

CROSSREFS

Cf. A079186, A079190, A079191. a(n)=A023813(n)*A023813(n-1).

Sequence in context: A316952 A317732 A179151 * A278384 A114133 A221233

Adjacent sequences:  A079186 A079187 A079188 * A079190 A079191 A079192

KEYWORD

nonn

AUTHOR

Christian van den Bosch (cjb(AT)cjb.ie), Jan 03 2003

EXTENSIONS

Edited and extended by Christian G. Bower, Dec 12 2003

STATUS

approved

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Last modified October 21 11:42 EDT 2019. Contains 328296 sequences. (Running on oeis4.)