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A179424 Number of ways to place 4 nonattacking kings on an n X n toroidal board. 10
0, 0, 0, 12, 575, 9837, 63553, 265008, 853497, 2312925, 5532967, 12037068, 24293243, 46125317, 83243925, 143918272, 239811333, 387002853, 607226187, 929346700, 1391111127, 2041198973, 2941608713, 4170413232, 5824920625, 8025278157, 10918558863, 14683371948, 19535039827, 25731386325 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,4
LINKS
FORMULA
Explicit formula: a(n) = 1/24*n^2*(n^6-54*n^4+1019*n^2-6798), n>=5.
G.f.: x^4*(160*x^9 - 963*x^8 + 2054*x^7 - 1308*x^6 - 963*x^5 - 375*x^4 + 5288*x^3 - 5094*x^2 - 467*x - 12)/(x-1)^9.
MATHEMATICA
CoefficientList[Series[x^3 (160 x^9 - 963 x^8 + 2054 x^7 - 1308 x^6 - 963 x^5 - 375 x^4 + 5288 x^3 - 5094 x^2 -467 x - 12) / (x - 1)^9, {x, 0, 50}], x] (* Vincenzo Librandi, Jun 01 2013 *)
CROSSREFS
Sequence in context: A192604 A192605 A192606 * A316977 A283490 A159722
KEYWORD
nonn,easy
AUTHOR
Vaclav Kotesovec, Jan 07 2011
STATUS
approved

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Last modified June 21 21:50 EDT 2024. Contains 373559 sequences. (Running on oeis4.)