A309746 - OEIS

%I #16 Sep 06 2019 01:46:18

%S 1,0,0,2,0,0,0,6,0,36,0,72,332,1596,6972

%N Number of ways of placing 2*n-1 nonattacking queens on a hexagonal board with edge-length n in Glinski's hexagonal chess.

%C Conjecture: for n >= 12 is a(n) > 0. Proved for n <= 20. - _Vaclav Kotesovec_, Sep 06 2019

%H Chess variants, <a href="https://www.chessvariants.com/hexagonal.dir/hexagonal.html">Glinski's Hexagonal Chess</a>

%H Vaclav Kotesovec, <a href="/A309746/a309746.jpg">Examples for n = 4, 8, 10, 12, 13 and 14</a>

%H Vaclav Kotesovec, <a href="/A309746/a309746_1.jpg">Examples for n = 15, 16, 17, 18, 19 and 20</a>

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Hexagonal_chess#Gli%C5%84ski&#39;s_hexagonal_chess">Hexagonal chess - Gliński's hexagonal chess</a>

%Y Cf. A002047, A003215, A309260, A309669.

%K nonn,more

%O 1,4

%A _Vaclav Kotesovec_, Aug 15 2019

%E a(15) from _Vaclav Kotesovec_, Aug 28 2019