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A231125
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Number of (n+1) X (2+1) white-square subarrays of 0..2 arrays with no element equal to a strict majority of its diagonal and antidiagonal neighbors, with values 0..2 introduced in row major order.
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1
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2, 8, 40, 176, 808, 3584, 16368, 72640, 331648, 1471872, 6719936, 29823488, 136161152, 604291584, 2758934016, 12244319232, 55902265856, 248097701888, 1132706802688, 5027022614528, 22951211032576, 101858889359360
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OFFSET
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1,1
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LINKS
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FORMULA
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Empirical: a(n) = 22*a(n-2) - 36*a(n-4) + 16*a(n-6).
Empirical g.f.: 2*x*(1 + 4*x - 2*x^2) / (1 - 22*x^2 + 36*x^4 - 16*x^6). - Colin Barker, Sep 26 2018
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EXAMPLE
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Some solutions for n=5:
..0..x..1....0..x..0....0..x..1....0..x..0....0..x..1....0..x..0....0..x..1
..x..2..x....x..1..x....x..2..x....x..1..x....x..2..x....x..1..x....x..2..x
..1..x..2....2..x..0....2..x..0....0..x..2....1..x..2....1..x..1....0..x..0
..x..1..x....x..1..x....x..1..x....x..0..x....x..1..x....x..2..x....x..2..x
..2..x..0....2..x..0....2..x..0....2..x..0....0..x..0....2..x..0....0..x..2
..x..2..x....x..0..x....x..0..x....x..2..x....x..2..x....x..0..x....x..0..x
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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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