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A280064
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Number of n X 3 0..1 arrays with no element unequal to a strict majority of its horizontal, vertical and antidiagonal neighbors and with new values introduced in order 0 sequentially upwards.
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1
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1, 2, 5, 15, 39, 104, 281, 771, 2122, 5858, 16174, 44694, 123510, 341403, 943694, 2608709, 7211359, 19935055, 55108220, 152341402, 421132682, 1164181573, 3218268552, 8896600238, 24593808939, 67987267220, 187944382019, 519554527901
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OFFSET
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1,2
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..210
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FORMULA
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Empirical: a(n) = 3*a(n-1) + a(n-2) - 6*a(n-3) + 5*a(n-4) - 2*a(n-5) - 2*a(n-6) - a(n-7) for n>9.
Empirical g.f.: x*(1 + x)*(1 - 2*x + 4*x^3 - 8*x^4 + 2*x^5 - x^6 - x^7) / ((1 - x + x^2)*(1 - 2*x - 4*x^2 + 4*x^3 + 3*x^4 + x^5)). - Colin Barker, Feb 12 2019
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EXAMPLE
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Some solutions for n=4:
..0..0..0. .0..1..1. .0..1..1. .0..0..0. .0..0..0. .0..0..0. .0..0..0
..0..0..0. .0..1..1. .0..1..1. .0..0..0. .0..0..0. .1..1..0. .0..0..0
..0..1..1. .0..1..1. .0..0..1. .0..0..1. .1..1..0. .1..1..0. .1..1..1
..1..1..1. .0..0..0. .0..0..1. .0..1..1. .1..1..0. .1..0..0. .1..1..1
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CROSSREFS
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Column 3 of A280069.
Sequence in context: A258121 A242823 A059840 * A148342 A148343 A148344
Adjacent sequences: A280061 A280062 A280063 * A280065 A280066 A280067
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin, Dec 25 2016
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STATUS
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approved
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