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A214012
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Number of 3X3 nonnegative integer matrices with row and column i=1..3 having sum <= i*n
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2
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271, 7722, 85639, 564041, 2663506, 9976732, 31499434, 87205393, 217519577, 498458246, 1064675833, 2143185161, 4101100212, 7511389208, 13241320196, 22569031649, 37334466803, 60131772546, 94551181659, 145479371081
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = (n+3) *(n+2) *(n+1) *(3493*n^6 +23853*n^5 +62185*n^4 +81783*n^3 +58531*n^2 +22470*n +3780)/22680;
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EXAMPLE
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Some solutions for n=3
..0..0..1....0..0..2....3..0..0....0..0..3....0..0..3....0..0..0....2..0..0
..2..0..0....2..1..0....0..6..0....1..2..0....1..0..0....0..0..0....0..1..0
..0..6..0....0..0..5....0..0..9....2..1..0....0..3..4....0..4..0....1..2..0
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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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