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A270051
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Number of n X n 0..4 arrays with some element plus some horizontally or vertically adjacent neighbor totalling four exactly once.
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0
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0, 240, 385200, 4410058320, 446901694424400, 431802177781617762960, 4120579270516550893026428880, 396051988194462616335989531581823280, 388077749523667550173285586776073430011586480
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OFFSET
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1,2
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COMMENTS
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LINKS
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EXAMPLE
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Some solutions for n=2
..1..2. .0..3. .2..2. .1..1. .3..0. .1..2. .1..0. .0..4. .1..0. .2..3
..3..4. .0..1. .4..1. .4..3. .2..2. .4..0. .3..2. .0..2. .1..4. .2..3
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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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