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A224035
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Number of n X 5 0..1 arrays with antidiagonals unimodal and rows and diagonals nondecreasing.
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1
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6, 26, 85, 252, 734, 2149, 6321, 18673, 55373, 164729, 491332, 1468446, 4395388, 13170815, 39497285, 118511408, 355728667, 1068051097, 3207330581, 9632722080, 28932821313, 86907496260, 261060029437, 784214341324, 2355790958452
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 6*a(n-1) - 10*a(n-2) + a(n-3) + 6*a(n-4) + a(n-5) - 4*a(n-6) + 4*a(n-7) - 4*a(n-8) + 8*a(n-9) for n>10.
Empirical g.f.: x*(6 - 10*x - 11*x^2 - 4*x^3 + 10*x^4 + 18*x^5 + 3*x^6 - 14*x^7 - 4*x^9) / ((1 - 2*x)*(1 - 4*x + 2*x^2 + 3*x^3 - x^5 + 2*x^6 + 4*x^8)). - Colin Barker, Aug 26 2018
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EXAMPLE
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Some solutions for n=3:
..0..0..0..0..0....0..0..0..1..1....0..0..0..0..0....0..0..0..1..1
..0..1..1..1..1....0..1..1..1..1....0..1..1..1..1....0..1..1..1..1
..1..1..1..1..1....0..1..1..1..1....0..0..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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