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A253491
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Number of (n+1) X (4+1) 0..2 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.
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1
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3639, 5386, 6476, 10477, 19475, 40117, 89339, 211597, 527555, 1373797, 3709259, 10309117, 29295635, 84629077, 247377179, 729117037, 2161327715, 6431941957, 19191749099, 57367099357, 171685007795, 514222448437, 1541002201019
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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>6.
Empirical: a(n) = 49*3^(n-1) + 794*2^(n-1) + 2802 for n>3.
G.f.: x*(3639 - 16448*x + 14189*x^2 + 9033*x^3 - 4467*x^4 - 342*x^5) / ((1 - x)*(1 - 2*x)*(1 - 3*x)).
a(n) = 2802 + 397*2^n + 49*3^(n-1) for n>3.
(End)
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EXAMPLE
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Some solutions for n=4:
..0..1..1..0..0....0..2..1..1..2....0..0..1..2..0....1..2..2..2..1
..0..1..1..0..0....1..1..0..0..1....0..0..1..2..0....1..1..1..1..0
..1..2..2..1..1....2..2..1..1..2....0..0..1..2..0....1..1..1..1..0
..0..1..1..0..0....1..1..0..0..1....0..0..1..2..0....1..1..1..1..0
..1..2..2..1..1....2..2..1..1..2....0..0..1..2..1....1..1..1..2..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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