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A202330
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Number of (n+1) X 4 binary arrays with consecutive windows of two bits considered as a binary number nondecreasing in every row and column.
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1
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36, 82, 162, 289, 478, 746, 1112, 1597, 2224, 3018, 4006, 5217, 6682, 8434, 10508, 12941, 15772, 19042, 22794, 27073, 31926, 37402, 43552, 50429, 58088, 66586, 75982, 86337, 97714, 110178, 123796, 138637, 154772, 172274, 191218, 211681, 233742
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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) = (1/12)*n^4 + (4/3)*n^3 + (83/12)*n^2 + (44/3)*n + 13.
G.f.: x*(36 - 98*x + 112*x^2 - 61*x^3 + 13*x^4) / (1 - x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5).
(End)
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EXAMPLE
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Some solutions for n=5:
..0..0..0..1....0..0..0..0....0..0..0..1....0..0..1..0....0..0..1..0
..0..0..0..1....0..0..1..0....0..0..0..1....0..0..1..0....0..0..1..1
..0..0..0..1....0..0..1..0....0..0..0..1....0..0..1..0....0..0..1..1
..0..0..0..1....0..0..1..0....0..1..1..1....0..0..1..0....0..1..1..1
..0..0..1..1....0..0..1..0....1..1..1..1....0..0..1..1....0..1..1..1
..0..1..1..1....0..1..1..1....0..1..1..1....0..0..1..0....1..1..1..1
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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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