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A207303
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Number of n X 6 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 1 0 vertically.
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1
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19, 361, 1675, 4939, 11497, 23091, 41893, 70537, 112151, 170389, 249463, 354175, 489949, 662863, 879681, 1147885, 1475707, 1872161, 2347075, 2911123, 3575857, 4353739, 5258173, 6303537, 7505215, 8879629, 10444271, 12217735, 14219749
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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) = (4/15)*n^5 + (45/4)*n^4 + (199/6)*n^3 - (73/4)*n^2 - (373/30)*n + 5).
G.f.: x*(19 + 247*x - 206*x^2 - 76*x^3 + 53*x^4 - 5*x^5) / (1 - x)^6. - Colin Barker, Jun 21 2018
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.
(End)
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EXAMPLE
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Some solutions for n=4:
..1..0..0..1..0..0....1..1..0..0..1..1....0..0..1..0..0..1....0..0..1..0..0..1
..0..1..0..0..1..0....1..1..1..1..0..0....1..0..0..1..1..0....0..1..1..0..0..1
..1..1..0..0..1..0....1..1..0..0..1..1....1..0..0..1..0..0....0..1..1..0..0..1
..1..1..0..0..1..0....1..1..1..0..0..1....1..0..0..1..1..0....0..1..1..0..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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