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A217450
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Number of n X 1 arrays of the minimum value of corresponding elements and their horizontal and vertical neighbors in a random 0..2 n X 1 array.
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5
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3, 3, 9, 17, 37, 77, 163, 343, 723, 1523, 3209, 6761, 14245, 30013, 63235, 133231, 280707, 591427, 1246089, 2625409, 5531525, 11654477, 24555043, 51735495, 109002515, 229659507, 483874057, 1019483609, 2147969733, 4525598973
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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) = 2*a(n-1) + a(n-4).
Empirical g.f.: x*(3 - 3*x + 3*x^2 - x^3) / (1 - 2*x - x^4). - Colin Barker, Feb 19 2018
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EXAMPLE
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All solutions for n=3:
..1....2....0....2....1....2....0....1....0
..0....0....0....2....1....1....0....1....0
..0....0....2....2....1....1....1....2....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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