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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A079207 Number of isomorphism classes of associative non-commutative non-anti-associative non-anti-commutative closed binary operations on a set of order n, listed by class size. 9
0, 0, 0, 0, 0, 4, 6, 0, 0, 0, 4, 4, 0, 46, 73 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

A079202(n)+A079203(n)+A079204(n)+A079205(n)+A079197(n)+A079207(n)+A079208(n)+A079209(n)+A063524(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; 0,0; 0,0,4,6; 0,0,0,4,4,0,46,73

A079240(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 A079241(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 semigroups

CROSSREFS

Cf. A079202, A079203, A079204, A079205, A079197, A079208, A079209, A079240, A079241.

Sequence in context: A231407 A005927 A201529 * A259825 A276449 A056945

Adjacent sequences:  A079204 A079205 A079206 * A079208 A079209 A079210

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 | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 20 07:17 EDT 2018. Contains 316378 sequences. (Running on oeis4.)