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A223775
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Number of n X 6 0..1 arrays with rows and columns unimodal and antidiagonals nondecreasing.
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1
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22, 169, 707, 2164, 5573, 12975, 28346, 59231, 119555, 234348, 447489, 834107, 1520016, 2711565, 4740623, 8131175, 13696273, 22676975, 36938539, 59243658, 93628083, 145910759, 224378788, 340697347, 511106363, 757979538, 1111837505
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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) = (1/479001600)*n^12 + (1/26611200)*n^11 + (11/8709120)*n^10 + (1/53760)*n^9 + (6271/14515200)*n^8 + (493/115200)*n^7 + (320657/8709120)*n^6 + (157151/483840)*n^5 + (41441549/10886400)*n^4 - (451279/67200)*n^3 + (49282619/332640)*n^2 - (20927/44)*n + 563 for n>3.
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EXAMPLE
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Some solutions for n=3
..0..0..0..0..0..1....0..0..0..0..0..1....0..0..0..0..0..0....0..0..0..0..0..0
..0..0..1..1..1..1....0..0..0..1..1..0....0..0..0..0..1..0....0..0..0..0..0..0
..0..1..1..1..1..0....1..1..1..1..1..0....1..1..1..1..1..1....0..1..1..1..1..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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