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A038144 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. 4
0, 0, 0, 0, 0, 1, 2, 13, 67, 404, 2323, 13517, 76570, 429320, 2373965, 13004323, 70641985, 381260615, 2046521491, 10936624026, 58228136539 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

COMMENTS

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.

REFERENCES

J. V. Knop et al., On the total number of polyhexes, Match, No. 16 (1984), 119-134.

LINKS

Table of n, a(n) for n=1..21.

Craig Knecht, Tiling of a fixed pattern of holes in a frame.

Joseph Myers, Polyomino, polyhex and polyiamond tiling

CROSSREFS

Cf. A018190, A038143, A038147, A000228, A018190.

Sequence in context: A045764 A106999 A054566 * A097977 A136780 A301944

Adjacent sequences:  A038141 A038142 A038143 * A038145 A038146 A038147

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

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

STATUS

approved

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Last modified August 23 14:32 EDT 2019. Contains 326247 sequences. (Running on oeis4.)