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A283380
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Number of nX2 0..1 arrays with no 1 equal to more than two of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements.
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1
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0, 1, 3, 19, 91, 399, 1734, 7257, 29754, 120018, 477678, 1880898, 7339875, 28425538, 109368210, 418413378, 1592767290, 6036395895, 22786979315, 85714057229, 321381104832, 1201482684424, 4479736531496, 16661729383449, 61830609817953
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OFFSET
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1,3
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 9*a(n-1) -24*a(n-2) +18*a(n-3) -36*a(n-4) +111*a(n-5) -38*a(n-6) +150*a(n-7) -162*a(n-8) +135*a(n-9) -222*a(n-10) +177*a(n-11) -212*a(n-12) +186*a(n-13) -168*a(n-14) +160*a(n-15) -114*a(n-16) +99*a(n-17) -68*a(n-18) +48*a(n-19) -30*a(n-20) +16*a(n-21) -9*a(n-22) +3*a(n-23) -a(n-24)
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EXAMPLE
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Some solutions for n=4
..0..1. .1..1. .0..0. .0..1. .1..1. .1..1. .0..1. .1..1. .1..1. .1..1
..0..0. .1..1. .0..1. .1..1. .1..0. .0..0. .1..1. .0..1. .1..1. .1..1
..1..1. .0..0. .1..1. .0..1. .1..1. .1..1. .1..0. .1..1. .0..0. .0..0
..1..1. .0..1. .1..0. .1..1. .1..0. .1..1. .0..0. .0..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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