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A295980
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Number of n X 3 0..1 arrays with each 1 adjacent to 2 or 3 king-move neighboring 1s.
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1
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1, 15, 44, 110, 581, 2354, 8452, 35474, 146560, 580023, 2356053, 9619854, 38867687, 157518881, 639985423, 2594957421, 10522265148, 42696678744, 173200350255, 702516695938, 2849908304750, 11560960945608, 46896382885056
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OFFSET
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1,2
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LINKS
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FORMULA
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Empirical: a(n) = 4*a(n-1) - 2*a(n-2) + 21*a(n-3) - 44*a(n-4) - 12*a(n-5) - 34*a(n-6) + 33*a(n-7) + 4*a(n-8) + 14*a(n-9) + a(n-10).
Empirical g.f.: x*(1 + 11*x - 14*x^2 - 57*x^3 - 42*x^4 - 2*x^5 + 38*x^6 + 18*x^7 + 15*x^8 + x^9) / (1 - 4*x + 2*x^2 - 21*x^3 + 44*x^4 + 12*x^5 + 34*x^6 - 33*x^7 - 4*x^8 - 14*x^9 - x^10). - Colin Barker, Feb 22 2019
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EXAMPLE
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Some solutions for n=7:
..1..1..0. .1..1..1. .0..0..0. .1..0..0. .0..1..1. .0..0..0. .0..1..1
..1..0..1. .0..1..0. .0..1..1. .1..1..0. .1..0..1. .0..0..0. .0..0..1
..1..0..1. .0..0..0. .0..0..1. .0..0..0. .0..1..0. .1..1..0. .0..0..1
..0..1..1. .0..1..0. .0..0..0. .0..1..1. .0..0..1. .1..0..1. .0..1..1
..0..0..0. .1..0..1. .0..1..0. .1..0..1. .0..0..1. .0..0..1. .0..0..0
..1..1..0. .1..0..1. .0..1..1. .1..0..1. .0..1..0. .0..1..0. .0..0..0
..0..1..0. .0..1..1. .0..0..1. .1..1..0. .1..1..0. .1..1..0. .0..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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