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A188780
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Number of 5-turn bishop's tours on an n X n board summed over all starting positions
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1
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0, 0, 8, 584, 5464, 26360, 91120, 252720, 603696, 1288592, 2525400, 4620728, 7998984, 13219528, 21014336, 32306400, 48256608, 70282656, 100115880, 139819944, 191858360, 259112216, 344959120, 453289232, 588596368, 755991600
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OFFSET
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1,3
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 4*a(n-1) -3*a(n-2) -8*a(n-3) +14*a(n-4) -14*a(n-6) +8*a(n-7) +3*a(n-8) -4*a(n-9) +a(n-10)
Empirical: G.f.: 8*x^3*(1 + 69*x + 394*x^2 + 790*x^3 + 829*x^4 + 357*x^5 + 84*x^6)/((1-x)^7*(1+x)^3)
Empirical: a(n) = 51/4 - 913*n/10 + 69203*n^2/360 - 602*n^3/3 + 1007*n^4/9 - 473*n^5/15 + 631*n^6/180 + (-1)^n*(-51/4 + 25*n/2 - 23*n^2/8)
(End)
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EXAMPLE
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Some solutions for 4X4
..0..5..0..0....0..5..0..0....0..5..0..0....0..0..2..0....0..4..0..0
..1..0..4..0....0..0..1..0....0..0..3..0....0..5..0..3....0..0..3..0
..0..3..0..0....0..2..0..4....0..2..0..4....1..0..4..0....0..2..0..5
..0..0..2..0....0..0..3..0....1..0..0..0....0..0..0..0....0..0..1..0
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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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