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A223953
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Number of 6 X n 0..1 arrays with diagonals and antidiagonals unimodal and rows nondecreasing.
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1
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64, 729, 2024, 3645, 5951, 9919, 16845, 28558, 47721, 78071, 124691, 194314, 295659, 439799, 640561, 914958, 1283653, 1771455, 2407847, 3227546, 4271095, 5585487, 7224821, 9250990, 11734401, 14754727, 18401691, 22775882, 27989603, 34167751
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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) = (2/45)*n^6 + (67/36)*n^4 + 8*n^3 + (7757/180)*n^2 + 138*n + 1326 for n>4.
G.f.: x*(64 + 281*x - 1735*x^2 + 2546*x^3 - 335*x^4 - 1862*x^5 + 787*x^6 + 767*x^7 - 426*x^8 - 148*x^9 + 93*x^10) / (1 - x)^7.
a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>11.
(End)
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EXAMPLE
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Some solutions for n=3:
..0..1..1....0..0..0....1..1..1....1..1..1....0..0..1....1..1..1....0..0..1
..0..0..0....0..0..0....0..1..1....0..1..1....0..1..1....0..0..1....0..0..1
..0..0..0....0..0..1....1..1..1....0..0..0....0..0..0....0..0..0....0..0..0
..0..0..0....0..0..1....1..1..1....0..0..0....0..0..0....0..0..1....0..1..1
..0..1..1....0..1..1....0..0..1....0..1..1....0..0..1....0..0..1....1..1..1
..0..0..0....0..0..1....0..0..0....0..0..1....1..1..1....0..0..1....0..0..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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