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%I #7 Sep 12 2015 11:00:28
%S 0,0,0,216,38070,1314600,21191208,207830308,1442794332,7775083960,
%T 34530764200,131660992164,443702617356,1350258600008,3771242866680,
%U 9789675562020,23856321869260,55015308882264,120855465245464,254284702668580,514791197224860,1006655249550696
%N Number of ways to place 7 non-attacking ferses on an n X n board.
%C Fers is a leaper [1,1].
%H V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Non-attacking chess pieces</a>
%F a(n) = n^14/5040 - n^12/48 + n^11/30 + 673n^10/720 - 17n^9/6 - 1019n^8/48 + 197n^7/2 + 9772n^6/45 - 3443n^5/2 + 47n^4/4 + 74259n^3/5 - 1816352n^2/105 - 49376n + 90660, n>=6.
%F G.f.: 2*x^4*(125*x^16 - 1785*x^15 + 11715*x^14 - 50121*x^13 + 158605*x^12 - 367485*x^11 + 570175*x^10 - 533381*x^9 + 460395*x^8 - 1262515*x^7 + 2731225*x^6 - 1795227*x^5 - 5484089*x^4 - 2685639*x^3 - 383115*x^2 - 17415*x - 108)/(x-1)^15.
%Y Cf. A187239, A201243, A201244, A201245, A201246, A201247.
%K nonn
%O 1,4
%A _Vaclav Kotesovec_, Nov 28 2011
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