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A359520
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Number of free holey polyominoes of n cells with simply-connected interiors.
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2
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0, 0, 0, 0, 0, 0, 1, 5, 35, 179, 909, 4285, 19702, 88040, 386826, 1674852, 7174436, 30462009
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OFFSET
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1,8
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LINKS
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FORMULA
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a(n) = A342537(n) - A000104(n) (simply connected polyominoes minus unholey polyominoes).
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EXAMPLE
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a(7) = 1 because of the holey heptomino.
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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