A079179 Number of anti-associative closed binary operations on a set of order n.

1, 0, 2, 52, 421560

Offset: 0

Author

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

Keywords

• nonn
• more

Links

• Christian van den Bosch, Closed binary operations on small sets
• Index entries for sequences related to groupoids

Crossrefs

Cf. A079176, A079180 (isomorphism classes), A079181, A079210.

Formula

a(n) = A002489(n) - A079176(n).

a(n) = Sum_{k>=1} A079181(n,k)*A079210(n,k).

Extensions

a(0)=1 prepended and a(1) corrected by Kamil Zabielski, Aug 28 2024