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A079200 Number of isomorphism classes of associative non-commutative closed binary operations on a set of order n, listed by class size. 6
0, 2, 0, 2, 0, 4, 6, 2, 0, 0, 4, 5, 0, 46, 73 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A079194(n)+A079197(n)+A079200(n)+A079201(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; 2,0,4,6; 2,0,0,4,5,0,46,73

A079198(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 A079199(x).

LINKS

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

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

CROSSREFS

Cf. A079194, A079197, A079198, A079199, A079201.

Sequence in context: A029186 A072680 A067770 * A011420 A035686 A037228

Adjacent sequences:  A079197 A079198 A079199 * A079201 A079202 A079203

KEYWORD

nonn,tabf

AUTHOR

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

STATUS

approved

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Last modified May 22 14:53 EDT 2013. Contains 225552 sequences.