A079182 Number of non-commutative closed binary operations on a set of order n.

0, 8, 18954, 4293918720, 298023193359375000, 10314424798468598595531571200, 256923577521058877628624940679495660344806, 6277101735386680763835789098689112757675628661308013936640

Offset

1,2

Comments

A023813(n) + A079182(n) = A002489(n).

Each a(n) is equal to the sum of the products of each element in row n of A079184 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

a(n) = n^(n^2)-n^((n^2-n)/2).

Mathematica

Table[n^(n^2)-n^((n^2+n)/2), {n, 1, 10}] (* Geoffrey Critzer, Jan 27 2013 *)

Crossrefs

Cf. A023813, A079178, A079180.

Sequence in context: A198404 A079597 A160743 * A079172 A173543 A067074

Adjacent sequences: A079179 A079180 A079181 * A079183 A079184 A079185

Keyword

nonn

Author

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

Extensions

More terms from Geoffrey Critzer, Jan 27 2013

Status

approved