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A201236
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Number of ways to place 2 non-attacking wazirs on an n X n toroidal board.
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8
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0, 2, 18, 88, 250, 558, 1078, 1888, 3078, 4750, 7018, 10008, 13858, 18718, 24750, 32128, 41038, 51678, 64258, 79000, 96138, 115918, 138598, 164448, 193750, 226798, 263898, 305368, 351538, 402750, 459358, 521728, 590238, 665278, 747250, 836568, 933658, 1038958
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OFFSET
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1,2
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COMMENTS
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A wazir is a leaper [0,1].
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LINKS
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FORMULA
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a(n) = n^2*(n^2-5)/2, n>=3.
G.f.: 2*x^2 * (2*x^5 - 9*x^4 + 15*x^3 - 9*x^2 - 4*x - 1)/(x-1)^5.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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