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A304196
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Number of free tree-like polycubes of size n in three dimensions.
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5
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1, 1, 2, 6, 21, 91, 484, 2817, 17788, 116741, 788081, 5414701, 37703459, 265182187
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OFFSET
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1,3
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COMMENTS
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A free tree-like polycube of size n in three dimensions is a face-connected set of n cells in the cubic lattice, up to translation, rotation and reflection, whose dual graph has no cycles.
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LINKS
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Alexandre Blondin Massé, Julien de Carufel, Alain Goupil, and Maxime Samson, Fully-leafed tree-like polyominoes and polycubes, In Combinatorial algorithms, volume 10765 of Lecture Notes of Computer Science, 28th International workshop, IWOCA 2017, Newcastle, NSW, Australia, Springer, 2018.
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CROSSREFS
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Cf. A118356 (fixed tree-like 3d-polycubes), A304198 (free tree-like 4d-polycubes), A131482 (free tree-like polyominoes).
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KEYWORD
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nonn,hard,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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