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A179403 Number of ways to place 2 nonattacking kings on an n X n toroidal board. 10
0, 0, 0, 56, 200, 486, 980, 1760, 2916, 4550, 6776, 9720, 13520, 18326, 24300, 31616, 40460, 51030, 63536, 78200, 95256, 114950, 137540, 163296, 192500, 225446, 262440, 303800, 349856, 400950 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,4
LINKS
FORMULA
Explicit formula: a(n) = 1/2*n^2*(n-3)*(n+3), n>=3.
G.f.: 2*x^4*(x-2)*(5*x^2 - 13*x + 14)/(x-1)^5.
MATHEMATICA
CoefficientList[Series[2 x^3 (x-2) (5 x^2 - 13 x + 14) / (x - 1)^5, {x, 0, 50}], x] (* Vincenzo Librandi, Jun 01 2013 *)
CROSSREFS
Cf. A061995.
Sequence in context: A264303 A200833 A241611 * A158481 A325306 A193428
KEYWORD
nonn,easy
AUTHOR
Vaclav Kotesovec, Jan 07 2011
STATUS
approved

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Last modified March 28 17:25 EDT 2024. Contains 371254 sequences. (Running on oeis4.)