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 A309746 #16 Sep 06 2019 01:46:18 %S A309746 1,0,0,2,0,0,0,6,0,36,0,72,332,1596,6972 %N A309746 Number of ways of placing 2*n-1 nonattacking queens on a hexagonal board with edge-length n in Glinski's hexagonal chess. %C A309746 Conjecture: for n >= 12 is a(n) > 0. Proved for n <= 20. - _Vaclav Kotesovec_, Sep 06 2019 %H A309746 Chess variants, <a href="https://www.chessvariants.com/hexagonal.dir/hexagonal.html">Glinski's Hexagonal Chess</a> %H A309746 Vaclav Kotesovec, <a href="/A309746/a309746.jpg">Examples for n = 4, 8, 10, 12, 13 and 14</a> %H A309746 Vaclav Kotesovec, <a href="/A309746/a309746_1.jpg">Examples for n = 15, 16, 17, 18, 19 and 20</a> %H A309746 Wikipedia, <a href="https://en.wikipedia.org/wiki/Hexagonal_chess#Gli%C5%84ski's_hexagonal_chess">Hexagonal chess - Gliński's hexagonal chess</a> %Y A309746 Cf. A002047, A003215, A309260, A309669. %K A309746 nonn,more %O A309746 1,4 %A A309746 _Vaclav Kotesovec_, Aug 15 2019 %E A309746 a(15) from _Vaclav Kotesovec_, Aug 28 2019