A075213 Number of polyhexes with n cells that tile the plane isohedrally but not by translation or by 180-degree rotation (Conway criterion).

0, 0, 0, 0, 1, 1, 33, 88, 611, 1803, 2985, 21250, 23564, 100221, 392655, 438188, 433150, 4762862, 2327445, 18839643, 46717154

Offset

1,7

Comments

A tiling is isohedral if the symmetries of the tiling act transitively on the tiles; a shape is anisohedral if it tiles the plane, but not isohedrally.

References

Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Section 9.4.

Links

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

Joseph Myers, Polyhex tiling

Crossrefs

Cf. A070766, A075207, A075208, A075209, A075210, A075211, A075212, A075214, A075215, A075204, A075222.

Sequence in context: A292366 A080200 A067705 * A231392 A231460 A114069

Adjacent sequences: A075210 A075211 A075212 * A075214 A075215 A075216

Keyword

hard,nonn

Author

Joseph Myers, Sep 08 2002

Extensions

More terms from Joseph Myers, Nov 08 2003

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), May 05 2007

Status

approved