cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A385041 Number of isomorphism classes of virtual quandles of order n.

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%I A385041 #14 Aug 06 2025 19:34:28
%S A385041 1,1,2,8,26,104,467,2540,18419
%N A385041 Number of isomorphism classes of virtual quandles of order n.
%C A385041 A virtual quandle is a quandle equipped with a distinguished quandle automorphism. Two virtual quandles (Q1,f1), (Q2,f2) are isomorphic if there exists a quandle isomorphism g: Q1 -> Q2 such that g*f1 = f2*g.
%H A385041 Alessia Cattabriga and Timur Nasybullov, <a href="https://doi.org/10.1007/s13398-017-0445-0">Virtual quandle for links in lens spaces</a>, RACSAM, 112 (2008), no. 3, 657-669.
%H A385041 Vassily Olegovich Manturov, <a href="https://doi.org/10.1023/A:1016258728022">On invariants of virtual links</a>, Acta Applicandae Mathematicae, 72 (2002), no. 3, 295-309.
%H A385041 Lực Ta, <a href="https://github.com/luc-ta/Virtual-Rack-Classification">Virtual-Rack Classification</a>, GitHub, 2025.
%H A385041 Lực Ta, <a href="https://arxiv.org/abs/2506.16536">Enumeration of virtual quandles up to isomorphism</a>, arXiv:2506.16536 [math.GT], 2025. See p. 5.
%o A385041 (GAP) See Ta, GitHub link
%Y A385041 Cf. A385040, A383145, A181769, A181770.
%Y A385041 Other sequences related to racks and quandles: A383144, A181771, A176077, A179010, A193024, A254434, A177886, A196111, A226173, A236146, A248908, A165200, A242044, A226193, A242275, A243931, A257351, A198147, A225744, A226172, A226174, A383828-A383831, A383145, A383146, A178432
%K A385041 nonn,hard,more
%O A385041 0,3
%A A385041 _Luc Ta_, Jun 16 2025
%E A385041 a(4)-a(8) corrected by _Luc Ta_, Jul 05 2025