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A253455
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Number of (n+1) X (7+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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48293, 74324, 89556, 114717, 170184, 285681, 526430, 1036512, 2142374, 4611192, 10320110, 24051792, 58456694, 148091112, 389833790, 1060740672, 2964819014, 8459769432, 24510051470, 71791759152, 211898605334, 628742590152
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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) + 6631*2^(n-1) + 59197 for n>6.
Empirical g.f.: x*(48293 - 215434*x + 174835*x^2 + 105187*x^3 + 21054*x^4 - 10872*x^5 - 3934*x^6 - 681*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..2..2..1..1..1..1....0..1..1..2..2..1..2..2....0..2..1..0..1..1..2..0
..1..1..1..1..0..0..0..0....1..1..0..1..1..0..1..1....1..2..1..0..1..1..2..0
..1..1..1..1..0..0..0..0....2..2..1..2..2..1..2..2....1..2..1..0..1..1..2..0
..1..1..1..1..0..0..0..0....1..1..0..1..1..0..1..1....1..2..1..0..1..1..2..1
..2..2..2..2..1..1..1..2....1..1..0..1..1..0..1..1....1..2..1..0..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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