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

1,3

Comments

A079188(n)+A079191(n)=A079171(n).

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

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

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

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

Links

Table of n, a(n) for n=1..15.

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

Index entries for sequences related to groupoids

Crossrefs

Cf. A079186, A079187, A079191.

Sequence in context: A363935 A033918 A136467 * A076810 A303144 A370451

Adjacent sequences: A079185 A079186 A079187 * A079189 A079190 A079191

Keyword

nonn,tabf

Author

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

Status

approved