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A253454
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Number of (n+1) X (6+1) 0..2 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally and vertically.
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1
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19701, 31630, 39463, 52912, 83003, 147332, 285681, 590963, 1287225, 2936843, 7007361, 17462243, 45313545, 121840763, 337369041, 955847123, 2755067865, 8040303083, 23671154721, 70114001603, 208543126185, 622031667803
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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) = 6*a(n-1) - 11*a(n-2) + 6*a(n-3) for n>9.
Empirical: a(n) = 529*3^(n-3) + 3431*2^(n-1) + 23248 for n>6.
Empirical g.f.: x*(19701 - 86576*x + 66394*x^2 + 45858*x^3 + 9844*x^4 - 5432*x^5 - 2750*x^6 - 489*x^7 - 54*x^8) / ((1 - x)*(1 - 2*x)*(1 - 3*x)). - Colin Barker, Dec 13 2018
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EXAMPLE
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Some solutions for n=4:
..0..1..1..0..1..0..0....0..1..0..2..2..2..2....0..2..1..1..2..0..1
..2..2..2..1..2..1..1....2..2..0..1..0..0..0....0..2..1..1..2..0..1
..1..1..1..0..1..0..0....2..2..0..1..0..0..0....0..2..1..1..2..0..1
..1..1..1..0..1..0..0....2..2..0..1..0..0..1....0..2..1..1..2..0..1
..2..2..2..1..2..1..1....2..2..0..1..0..0..2....0..2..1..1..2..0..2
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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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