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A079208 Number of isomorphism classes of associative non-commutative non-anti-associative anti-commutative closed binary operations on a set of order n, listed by class size. 9
0, 2, 0, 2, 0, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

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; 2,0; 2,0,0,0; 2,0,0,0,1,0,0,0

A079242(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 A079243(x).

LINKS

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

Index entries for sequences related to semigroups

CROSSREFS

Cf. A079202, A079203, A079204, A079205, A079197, A079207, A079209, A079242, A079243.

Sequence in context: A193526 A160498 A089800 * A069851 A197629 A198255

Adjacent sequences:  A079205 A079206 A079207 * A079209 A079210 A079211

KEYWORD

nonn,tabf

AUTHOR

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

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Last modified February 17 19:13 EST 2012. Contains 206085 sequences.