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A225351
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Number of 11Xn -1,1 arrays such that the sum over i=1..11,j=1..n of i*x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute n-across galley oarsmen left-right at 11 fore-aft positions so that there are no turning moments on the ship)
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1
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0, 1113, 0, 103583, 0, 2102597, 0, 20044255, 0, 121558241, 0, 545572495, 0, 1975264495, 0, 6087969941, 0, 16555930825, 0, 40733826807, 0, 92339940289, 0, 195519292147, 0, 390766431925, 0, 743286869427, 0, 1354483437063, 0
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 2*a(n-4) +a(n-6) -a(n-12) -3*a(n-14) -2*a(n-16) +3*a(n-24) +4*a(n-26) +2*a(n-28) +3*a(n-30) +2*a(n-32) -3*a(n-34) -5*a(n-36) -4*a(n-38) -5*a(n-40) -4*a(n-42) -a(n-44) +2*a(n-46) +4*a(n-48) +6*a(n-50) +6*a(n-52) +4*a(n-54) +2*a(n-56) -a(n-58) -4*a(n-60) -5*a(n-62) -4*a(n-64) -5*a(n-66) -3*a(n-68) +2*a(n-70) +3*a(n-72) +2*a(n-74) +4*a(n-76) +3*a(n-78) -2*a(n-86) -3*a(n-88) -a(n-90) +a(n-96) +2*a(n-98) -a(n-102)
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EXAMPLE
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Some solutions for n=4
.-1.-1.-1..1....1..1..1..1...-1.-1.-1..1....1..1..1..1...-1..1..1..1
.-1.-1..1..1...-1.-1.-1..1...-1.-1..1..1...-1.-1.-1..1...-1.-1.-1.-1
..1..1..1..1...-1.-1.-1..1...-1.-1..1..1...-1.-1..1..1...-1..1..1..1
.-1.-1..1..1...-1..1..1..1...-1..1..1..1...-1.-1.-1..1...-1.-1..1..1
.-1.-1.-1.-1...-1.-1..1..1...-1.-1..1..1...-1.-1..1..1...-1.-1.-1..1
..1..1..1..1...-1.-1.-1..1...-1.-1..1..1...-1.-1..1..1...-1..1..1..1
.-1.-1..1..1...-1.-1..1..1...-1..1..1..1...-1.-1.-1.-1...-1..1..1..1
.-1.-1..1..1...-1.-1.-1.-1...-1.-1.-1..1...-1.-1..1..1...-1.-1.-1..1
.-1.-1.-1..1...-1.-1..1..1...-1..1..1..1....1..1..1..1...-1..1..1..1
.-1.-1.-1.-1...-1..1..1..1...-1.-1..1..1...-1.-1..1..1...-1.-1.-1.-1
..1..1..1..1...-1..1..1..1...-1.-1.-1..1...-1.-1..1..1...-1..1..1..1
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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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