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A201246 Number of ways to place 5 non-attacking ferses on an n X n board. 7

%I

%S 0,0,12,780,16286,159452,992412,4567836,16959488,53617596,149618794,

%T 377841356,879314442,1911495356,3922051616,7657895196,14321764860,

%U 25791609308,44921419134,75946019596,125016699158,200899440924,315872975684,486869916572,736910896536

%N Number of ways to place 5 non-attacking ferses on an n X n board.

%C Fers is a leaper [1,1].

%H Vincenzo Librandi, <a href="/A201246/b201246.txt">Table of n, a(n) for n = 1..1000</a>

%H V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Non-attacking chess pieces</a>, 6ed, p.415

%F a(n) = n^10/120 - 5n^8/12 + 2n^7/3 + 191n^6/24 - 24n^5 - 661n^4/12 + 880n^3/3 - 937n^2/15 - 1176n + 1436, n>=4.

%F G.f.: 2x^3*(11x^11 - 135x^10 + 549x^9 - 993x^8 + 1172x^7 - 2968x^6 + 7085x^5 - 4715x^4 - 10613x^3 - 4183x^2 - 324x - 6)/(x-1)^11.

%t CoefficientList[Series[2 x^2 (11 x^11 - 135 x^10 + 549 x^9 - 993 x^8 + 1172 x^7 - 2968 x^6 + 7085 x^5 - 4715x^4 - 10613 x^3 - 4183 x^2- 324 x - 6)/(x-1)^11, {x, 0, 40}], x] (* _Vincenzo Librandi_, Apr 30 2013 *)

%Y Cf. A172129, A201243, A201244, A201245, A201247, A201248.

%K nonn,easy

%O 1,3

%A _Vaclav Kotesovec_, Nov 28 2011

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Last modified May 28 04:02 EDT 2022. Contains 354112 sequences. (Running on oeis4.)