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A221274
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Number of nX4 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with every occupancy equal to zero or two
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1
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1, 25, 100, 1089, 6724, 56644, 400689, 3122289, 23049601, 175350564, 1311815961, 9905822784, 74413292944, 560619075025, 4216817073121, 31746204178129, 238880949939076, 1798010762343849, 13531178521076836, 101839561889056996
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OFFSET
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1,2
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COMMENTS
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Column 4 of A221275
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..21
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FORMULA
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Empirical: a(n) = 7*a(n-1) +16*a(n-2) -105*a(n-3) +108*a(n-4) +10*a(n-5) -56*a(n-6) -53*a(n-7) +23*a(n-8) -6*a(n-9) +a(n-10)
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EXAMPLE
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Some solutions for n=4
..0..2..2..0....0..2..2..0....0..0..2..2....0..0..2..0....2..2..2..0
..2..0..0..0....2..0..0..2....2..2..0..0....0..2..2..2....0..2..0..2
..0..2..2..0....2..2..0..2....0..0..2..2....2..0..2..2....0..0..2..0
..0..2..2..2....0..0..2..0....0..2..2..0....0..2..0..0....2..2..0..0
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CROSSREFS
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Sequence in context: A016850 A309779 A356533 * A042220 A114254 A042222
Adjacent sequences: A221271 A221272 A221273 * A221275 A221276 A221277
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin Jan 09 2013
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STATUS
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approved
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