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A079184 Number of isomorphism classes of non-commutative closed binary operations on a set of order n, listed by class size. 4
0, 4, 2, 2, 8, 70, 3121, 2, 1, 14, 22, 275, 467, 48306, 178888897 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A079184(n)+A079185(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; 4,2; 2,8,70,3121; 2,1,14,22,275,467,48306,178888897

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 n is given by A079177(n).

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. A079182, A079183, A079185.

Sequence in context: A153810 A098134 A079191 * A095800 A055630 A182700

Adjacent sequences:  A079181 A079182 A079183 * A079185 A079186 A079187

KEYWORD

nonn,tabf

AUTHOR

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

STATUS

approved

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Last modified October 16 18:56 EDT 2019. Contains 328102 sequences. (Running on oeis4.)