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A208634
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Number of n X 5 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.
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1
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16, 47, 150, 494, 1652, 5572, 18888, 64216, 218704, 745616, 2543520, 8679776, 29625920, 101131840, 345250944, 1178690944, 4024163584, 13739075840, 46907582976, 160151393792, 546788836352, 1866849412096, 6373813684224
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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) = 6*a(n-1) - 10*a(n-2) + 4*a(n-3).
G.f.: x*(16 - 49*x + 28*x^2) / ((1 - 2*x)*(1 - 4*x + 2*x^2)).
a(n) = (3*2^(1+n) + (11-2*sqrt(2))*(2-sqrt(2))^n + (2+sqrt(2))^n*(11+2*sqrt(2))) / 4.
(End)
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EXAMPLE
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Some solutions for n=4:
..0..0..1..1..0....0..1..1..0..0....0..1..0..0..1....0..1..1..0..0
..1..0..0..1..1....0..0..1..1..0....1..0..1..0..0....1..0..1..1..1
..1..1..0..0..0....1..0..0..1..1....1..0..1..1..1....0..1..0..0..1
..0..1..1..1..0....0..1..0..0..0....1..0..0..0..1....1..0..1..0..1
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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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