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A203391
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Number of nX2 0..3 arrays with every nonzero element less than or equal to some NW, E or S neighbor
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1
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1, 16, 185, 1455, 10804, 83876, 661595, 5187181, 40522052, 316707721, 2476929279, 19371658984, 151484525968, 1184573677051, 9263247815357, 72438024528140, 566459469153425, 4429661481889999, 34639556932938188, 270878300837545724
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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) = 16*a(n-1) -100*a(n-2) +400*a(n-3) -1164*a(n-4) +2172*a(n-5) -2624*a(n-6) +2393*a(n-7) -1552*a(n-8) +736*a(n-9) -324*a(n-10)
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EXAMPLE
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Some solutions for n=4
..2..2....1..0....2..3....2..0....1..0....3..1....1..0....1..1....0..3....2..2
..0..2....2..0....1..3....2..2....1..0....3..3....2..0....0..2....0..3....1..2
..3..3....3..0....3..3....1..1....1..0....0..1....2..2....2..2....3..3....0..0
..0..3....3..3....0..3....0..0....1..1....0..0....1..1....0..2....3..3....0..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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