%I #9 Sep 12 2015 11:00:24
%S 1,6,36,412,4650,85358,1414678,32042312,710371744,20080400872,
%T 546562561108
%N Number of ways to place n nonattacking nightriders on an n X n board.
%C A nightrider is a fairy chess piece that can move any distance in a direction specified by a knight move.
%H V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Non-attacking chess pieces</a>
%Y Cf. A196814, A190393.
%K nonn,hard
%O 1,2
%A _Vaclav Kotesovec_, Dec 22 2011