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A302631
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Number of nX4 0..1 arrays with every element equal to 0, 1, 3 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
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1
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5, 17, 14, 33, 101, 248, 657, 1841, 4892, 13020, 35447, 95226, 255042, 688238, 1852413, 4976015, 13395869, 36053423, 96953152, 260865015, 701948030, 1888295155, 5080237927, 13668712238, 36773414080, 98934258153, 266178278368
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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) = a(n-1) +2*a(n-2) +9*a(n-3) -12*a(n-5) -13*a(n-6) +2*a(n-7) +17*a(n-8) +13*a(n-9) -6*a(n-10) -16*a(n-11) -12*a(n-12) +6*a(n-13) +12*a(n-14) +5*a(n-15) -8*a(n-16) -10*a(n-17) -4*a(n-18) +3*a(n-19) +3*a(n-20) +a(n-21) for n>25
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EXAMPLE
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Some solutions for n=5
..0..1..0..1. .0..1..0..1. .0..1..0..1. .0..1..0..1. .0..1..1..0
..0..1..0..0. .0..1..1..0. .0..1..1..0. .0..1..0..1. .1..0..1..0
..0..1..0..1. .1..0..1..0. .1..0..1..0. .1..0..0..1. .1..0..1..0
..0..1..0..1. .1..0..1..0. .1..0..1..0. .1..0..1..0. .1..0..1..0
..0..1..1..0. .1..0..0..1. .1..1..0..0. .1..0..1..0. .1..0..0..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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