%I #32 Nov 07 2023 14:43:51
%S 1,1,1,3,5,13,41,142,665,4288,36455,436672,6926801
%N Number of isomorphism classes of kei (involutory quandles) of order n.
%C The terms can be calculated by using the Mace4C system which is an isomorph-free model finder. - _Choiwah Chow_, Oct 30 2023
%H P. Jedlicka, A. Pilitowska, D. Stanovsky et al., <a href="http://arxiv.org/abs/1409.8396">The structure of medial quandles</a>, arXiv preprint 1409.8396 [math.GR], 2014.
%H David Joyce, <a href="http://dx.doi.org/10.1016/0022-4049(82)90077-9">A classifying invariant of knots, the knot quandle</a>, J. Pure Appl. Algebra 23 (1982) 37-65.
%H Sam Nelson, <a href="http://www1.cmc.edu/pages/faculty/VNelson/quandles.html">Quandles and Racks</a>
%H Mituhisa Takasaki, <a href="https://www.jstage.jst.go.jp/article/tmj1911/49/0/49_0_145/_article/-char/en">Abstraction of symmetric transformations</a> (also referenced as Abstractions of symmetric functions), Tohoku Math. J., 49 (1943), 143-207 [in Japanese].
%Y Cf. A181769, A226173, A242044.
%K nonn,hard,more
%O 0,4
%A _James McCarron_, Dec 21 2010
%E a(11)-a(12) from _Choiwah Chow_, Oct 30 2023