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A079194 Number of isomorphism classes of non-associative non-commutative closed binary operations on a set of order n, listed by class size. 6
0, 2, 2, 0, 8, 66, 3115, 0, 1, 14, 18, 270, 467, 48260, 178888824 (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; 2,2; 0,8,66,3115; 0,1,14,18,270,467,48260,178888824

A079192(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 A079193(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. A079192, A079193, A079197, A079200, A079201.

Sequence in context: A009803 A009615 A184011 * A179198 A117739 A243203

Adjacent sequences:  A079191 A079192 A079193 * A079195 A079196 A079197

KEYWORD

nonn,tabf

AUTHOR

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

STATUS

approved

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Last modified January 19 18:20 EST 2019. Contains 319309 sequences. (Running on oeis4.)