A244284 - OEIS

%I #6 Sep 12 2015 11:00:29

%S 1,6,84,1168,20502,525796,18939708,802444170,38934305898,2170312156170

%N Number of ways to place n nonattacking zebras on an n X n chessboard.

%C Zebra is a (fairy chess) leaper [2,3].

%H V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Non-attacking chess pieces</a>, 6ed, 2013, p.363

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Fairy_chess_piece">Fairy chess piece</a>

%F a(n) ~ n^(2*n)/n! * exp(-9/2).

%Y Cf. A172137, A172138, A172139, A172140.

%Y Cf. A201540, A201511, A201861, A201513.

%K nonn,hard,more

%O 1,2

%A _Vaclav Kotesovec_, Jun 25 2014