A079187 Number of isomorphism classes of non-anti-commutative closed binary operations (groupoids) on a set of order n.

1, 4, 2334, 147124304, 2216860823492185, 13395780829563177947362200, 48974776899548402559651008669035131863, 151979850442580207421627199010701131897617064179661376, 534046142973031436667769900555231150876473571233474760878454735694121879

Offset

1,2

Comments

Each a(n) is equal to the sum of the elements in row n of A079188.

Links

Table of n, a(n) for n=1..9.

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

Index entries for sequences related to groupoids

Formula

a(n) = A001329(n) - A079190(n), n > 1.

Crossrefs

Cf. A079186, A079188, A079190.

Sequence in context: A097476 A047676 A280790 * A131587 A066850 A066837

Adjacent sequences: A079184 A079185 A079186 * A079188 A079189 A079190

Keyword

nonn

Author

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

Extensions

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

a(9) from Sean A. Irvine, Aug 03 2025

Status

approved