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A075212 Number of polyhexes with n cells that tile the plane by translation or by 180-degree rotation (Conway criterion). 10
1, 1, 3, 7, 21, 75, 257, 930, 3104, 9265, 21304, 81392, 139612, 427454, 1176912, 2491134, 4319362, 16243200, 21965930, 76738851, 158374741 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

REFERENCES

Branko Gr├╝nbaum 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, A075213, A075214, A075215, A075203, A075221.

Sequence in context: A001576 A169587 A075211 * A173794 A049365 A031885

Adjacent sequences:  A075209 A075210 A075211 * A075213 A075214 A075215

KEYWORD

hard,nonn

AUTHOR

Joseph Myers, Sep 08 2002

EXTENSIONS

More terms from Joseph Myers, Nov 08 2003

a(20) and a(21) from Joseph Myers, Nov 21 2010

STATUS

approved

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Last modified March 25 07:34 EDT 2017. Contains 284047 sequences.