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A191552
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Number of n X n symmetric binary matrices with each 1 adjacent to no more than 2 diagonally or antidiagonally neighboring 1s
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1
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2, 8, 52, 528, 11275, 435987, 30448860, 3920809305, 920775496348, 394837552267029, 310020405028212730, 445022535834699088455, 1167728276848286755937076, 5603048100640429152817307256
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OFFSET
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1,1
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LINKS
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EXAMPLE
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Some solutions for n=4
..1..1..0..0....0..0..0..1....1..1..0..0....0..0..0..0....1..0..1..0
..1..1..1..0....0..0..0..1....1..1..1..0....0..0..1..0....0..0..1..0
..0..1..0..0....0..0..1..0....0..1..1..0....0..1..1..1....1..1..1..1
..0..0..0..1....1..1..0..0....0..0..0..0....0..0..1..1....0..0..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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