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A216986
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Number of city-block distance 1, pressure limit 2 movements in an nX3 array with each element moving exactly one horizontally or vertically, no element acquiring more than two neighbors, and without 2-loops
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1
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0, 14, 264, 4794, 83304, 1435808, 24673352, 423651134, 7272419728, 124829530972, 2142624332680, 36776621687102, 631243274484392, 10834813398096496, 185971344332908696, 3192056733158039014, 54789226054169999632
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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) = 24*a(n-1) -121*a(n-2) +28*a(n-3) +649*a(n-4) -844*a(n-5) +175*a(n-6) +80*a(n-7) -2*a(n-8)
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EXAMPLE
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Some solutions for n=3 (movement: 0=n 1=e 2=s 3=w)
..1..1..2....1..2..3....1..1..2....2..3..3....1..1..2....2..3..3....1..2..2
..1..0..3....0..1..0....1..0..2....1..2..0....0..0..3....2..3..0....0..3..3
..0..3..3....0..3..0....1..0..3....0..3..3....1..0..3....1..1..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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