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A341219
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Number of well-connected free polyominoes with n cells, where a polyomino is defined as well-connected if, for all the squares it contains, the removal of that single square would result in an intact polyomino.
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2
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1, 1, 1, 0, 1, 0, 1, 0, 3, 1, 6, 2, 25, 18, 88
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OFFSET
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0,9
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COMMENTS
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Examples of well-connected polyominoes are rectangles and loops:
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XXXX
XXXX (rectangle)
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XXX
X X (loop)
XXX
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LINKS
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EXAMPLE
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a(4) = 1 because the 2 X 2 square polyomino is the only tetromino to be well-connected. The removal of any single square always results in an intact tromino. In each of the other 4 tetrominoes, there is a square whose removal would result in something that is not an intact polyomino.
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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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