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.
%I A181770 #39 Aug 06 2025 16:00:15 %S A181770 1,1,2,6,19,74,353,2080,16023,159526,2093244,36265070,836395102, %T A181770 25794670618 %N A181770 Number of isomorphism classes of racks of order n. %C A181770 Also the number of isomorphism classes of Legendrian racks of order n; see Ta, "Good involutions...," Theorem 10.1. %C A181770 Also the number of isomorphism classes of GL-quandles of order n; see Ta, "Classification and...," Theorem 5.6. %H A181770 Přemysl Jedlička, Agata Pilitowska, and Anna Zamojska-Dzienio, <a href="https://arxiv.org/abs/1901.01471">Multipermutation set theoretic solutions of the Yang-Baxter equation of level 2</a>, arXiv:1901.01471 [math.QA], 2019. %H A181770 Sam Nelson, <a href="http://www1.cmc.edu/pages/faculty/VNelson/quandles.html">Quandles and Racks</a> %H A181770 Lực Ta, <a href="https://arxiv.org/abs/2505.08090">Good involutions of conjugation subquandles</a>, arXiv:2505.08090 [math.GT], 2025. %H A181770 Lực Ta, <a href="https://arxiv.org/abs/2504.12671">Classification and structure of generalized Legendrian racks</a>, arXiv:2504.12671 [math.GT], 2025. %H A181770 Petr Vojtěchovský and Seung Yeop Yang, <a href="https://doi.org/10.1090/mcom/3409">Enumeration of racks and quandles up to isomorphism</a>, Mathematics of Computation, 88 (2019), 2523-2540; arXiv:<a href="https://arxiv.org/abs/1911.04991">1911.04991</a> [math.QA], 2019. %Y A181770 Cf. A181769, A383144-A383146, A383828-A383831, A385040, A385041, A386231-A386234. %K A181770 nonn,hard,more %O A181770 0,3 %A A181770 _James McCarron_ %E A181770 a(9)-a(13) from Petr Vojtěchovský and Seung Yeop Yang added by _Andrey Zabolotskiy_, Jun 15 2022