A178432 - OEIS

A178432

Number of isomorphism classes of kei (involutory quandles) of order n.

1, 1, 1, 3, 5, 13, 41, 142, 665, 4288, 36455, 436672, 6926801

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,4

COMMENTS

The terms can be calculated by using the Mace4C system which is an isomorph-free model finder. - Choiwah Chow, Oct 30 2023

LINKS

Table of n, a(n) for n=0..12.

P. Jedlicka, A. Pilitowska, D. Stanovsky et al., The structure of medial quandles, arXiv preprint 1409.8396 [math.GR], 2014.

David Joyce, A classifying invariant of knots, the knot quandle, J. Pure Appl. Algebra 23 (1982) 37-65.

Sam Nelson, Quandles and Racks

Mituhisa Takasaki, Abstraction of symmetric transformations (also referenced as Abstractions of symmetric functions), Tohoku Math. J., 49 (1943), 143-207 [in Japanese].

CROSSREFS

Cf. A181769, A226173, A242044.

Sequence in context: A271667 A188583 A259932 * A236068 A057188 A128548

Adjacent sequences: A178429 A178430 A178431 * A178433 A178434 A178435

KEYWORD

nonn,hard,more

AUTHOR

James McCarron, Dec 21 2010

EXTENSIONS

a(11)-a(12) from Choiwah Chow, Oct 30 2023

STATUS

approved