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A079178 Number of isomorphism classes of non-anti-associative closed binary operations on a set of order n, listed by class size. 6
0, 2, 6, 3, 10, 78, 3229, 2, 1, 12, 30, 246, 495, 48427, 178914959 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A079178(n)+A079181(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; 2,6; 3,10,78,3229; 2,1,12,30,246,495,48427,178914959

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 x of this sequence is given by A079177(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. A079176, A079177, A079179.

Sequence in context: A180428 A130684 A295644 * A322365 A297553 A347558

Adjacent sequences: A079175 A079176 A079177 * A079179 A079180 A079181

KEYWORD

nonn,tabf

AUTHOR

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

STATUS

approved

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Last modified February 2 16:46 EST 2023. Contains 360023 sequences. (Running on oeis4.)