A190393 - OEIS

%I #19 Mar 13 2022 09:45:31

%S 1,2,6,24,120,144,28,1408,2025,86400,1782,1092096,4186,31360,

%T 241920000,23953408,140692,114108912,1092690

%N Number of ways to place n nonattacking nightriders on an n X n toroidal board.

%C A nightrider is a fairy chess piece that can move (proportionate to how a knight moves) in any direction.

%H Vaclav Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Number of ways of placing non-attacking queens, kings, bishops and knights</a> (in English and Czech).

%Y Cf. A172141, A173429, A051906.

%K nonn,nice,hard,more

%O 1,2

%A _Vaclav Kotesovec_, May 10 2011

%E Terms a(16)-a(17) from _Vaclav Kotesovec_, May 14 2011

%E Terms a(18)-a(19) from _Vaclav Kotesovec_, May 28 2011