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A038144
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Number of planar n-hexes, or polyhexes (in the sense of A000228, so rotations and reflections count as the same shape) with at least one hole.
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3
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0, 0, 0, 0, 0, 1, 2, 13, 67, 404, 2323, 13517, 76570, 429320, 2373965, 13004323, 70641985, 381260615, 2046521491, 10936624026, 58228136539
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OFFSET
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1,7
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COMMENTS
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Apparently the same as the number of hexagonal planar circulenes (planar rings of hexagons) with n cells, although the two sequences may in fact differ for large n.
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REFERENCES
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J. V. Knop et al., On the total number of polyhexes, Match, No. 16 (1984), 119-134.
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LINKS
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Table of n, a(n) for n=1..21.
Joseph Myers, Polyomino, polyhex and polyiamond tiling
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CROSSREFS
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Cf. A018190, A038143, A038147, A000228, A018190.
Sequence in context: A045764 A106999 A054566 * A097977 A136780 A128743
Adjacent sequences: A038141 A038142 A038143 * A038145 A038146 A038147
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane.
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EXTENSIONS
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More terms from Joseph Myers, May 05 2002
Further terms from Joseph Myers, Nov 06 2003
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), May 05 2007
Link edited by Joseph Myers, Nov 17 2010
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STATUS
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approved
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