A079188 Number of isomorphism classes of non-anti-commutative closed binary operations on a set of order n, listed by class size.

0, 0, 4, 1, 4, 44, 2285, 0, 0, 0, 24, 64, 212, 35240, 147088764

Offset: 1

Author

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

Keywords

• nonn
• tabf

Comments

Elements per row: 1,2,4,8,16,30,... (given by A027423, number of positive divisors of n!)

A079176(n) is equal to the sum of the products of each element in row n of this sequence and the corresponding element of A079210.

The sum of each row n of this sequence is given by A079177(n).

Examples

			First four rows:
  0;
  0, 4;
  1, 4, 44, 2285;
  0, 0, 0, 24, 64, 212, 35240, 147088764.
		

Links

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

Crossrefs

Cf. A027423, A079171, A079186, A079187, A079191.

Formula

a(n) = A079171(n) - A079191(n).