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Number of ways to place n nonattacking wazirs on an n X n board.
13

%I #26 Apr 16 2024 19:48:16

%S 1,1,2,22,405,10741,368868,15516804,771464278,44218721793,

%T 2868879752822,207739939478618,16602826428818482,1451305771147909684,

%U 137715836041691050398,14096224186664736126206,1547966111897855935957132,181519663430661533452513680,22636566614411901986006002896

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

%C Wazir is a leaper [0,1].

%H Vaclav Kotesovec, <a href="/A201511/b201511.txt">Table of n, a(n) for n = 0..21</a> (terms a(11)-a(18) computed by Peter Tittmann)

%H V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Non-attacking chess pieces</a>, 6ed, 2013, p. 382.

%H Peter Tittmann, <a href="http://www.staff.hs-mittweida.de/~peter/research/grids.html">Polynomials of nxn Grid Graphs</a> [broken link]

%F Asymptotics (Vaclav Kotesovec, Nov 29 2011): a(n) ~ n^(2n)/n!*exp(-5/2).

%Y Cf. A172225, A172226, A172227, A172228, A178409, A201507, A201508, A201510.

%Y Cf. A006506.

%Y Main diagonal of A232833.

%K nonn,nice,hard

%O 0,3

%A _Vaclav Kotesovec_, Dec 02 2011

%E a(19)-a(20) from _Vaclav Kotesovec_, Aug 30 2016

%E a(0)=1 prepended by _Alois P. Heinz_, Apr 16 2024