login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A079191 Number of isomorphism classes of anti-commutative closed binary operations on a set of order n, listed by class size. 4
1, 4, 2, 2, 8, 34, 952, 2, 1, 14, 6, 211, 283, 13570, 31843561 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

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: 1; 4,2; 2,8,34,952; 2,1,14,6,211,283,13570,31843561

A079189(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 A079190(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. A079188, A079189, A079190.

Sequence in context: A020777 A153810 A098134 * A079184 A095800 A055630

Adjacent sequences:  A079188 A079189 A079190 * A079192 A079193 A079194

KEYWORD

nonn,tabf

AUTHOR

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

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified November 22 22:27 EST 2014. Contains 249835 sequences.