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%I #15 Feb 18 2018 14:59:01
%S 0,0,9,79,454,1566,4103,9009,17484,30984,51221,80163,120034,173314,
%T 242739,331301,442248,579084,745569,945719,1183806,1464358,1792159,
%U 2172249,2609924
%N Number of ways to place 4 nonattacking kings on a 4 X n board.
%H Vincenzo Librandi, <a href="/A172203/b172203.txt">Table of n, a(n) for n = 1..1000</a>
%H V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Number of ways of placing non-attacking queens and kings on boards of various sizes</a>
%F a(n) = (64n^4 - 720n^3 + 3347n^2 - 7569n + 6894)/6, n>=3.
%F G.f.: -x^3*(68*x^4-4*x^3+149*x^2+34*x+9)/(x-1)^5. - _Vaclav Kotesovec_, Mar 24 2010
%t CoefficientList[Series[- x^2 (68 x^4 - 4 x^3 + 149 x^2 + 34 x + 9) / (x - 1)^5, {x, 0, 50}], x] (* _Vincenzo Librandi_, May 27 2013 *)
%Y Cf. A061997, A061990, A172202.
%K nonn,easy
%O 1,3
%A _Vaclav Kotesovec_, Jan 29 2010
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