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A239658
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Number of free triangular n-polyplets (triangular polyominoes connected at edges or corners), where turning over is allowed and holes are allowed.
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1
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1, 1, 3, 11, 75, 528, 4584, 40609, 373981, 3493723, 33079702, 316109657, 3044648053
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OFFSET
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0,3
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COMMENTS
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We get triangular polyominoes when connecting over edges only (rather than edges and corners); that is A000577. The square equivalent (that is, n-polyplets) is A030222. The neighborhood is also known as the Triangular Moore neighborhood, and equals the moves of the Tri-Chess king.
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LINKS
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CROSSREFS
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KEYWORD
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nonn,hard,more
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AUTHOR
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Abe Wits and Ragnar Groot Koerkamp, Nov 20 2020
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EXTENSIONS
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STATUS
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approved
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