OFFSET
1,3
COMMENTS
Equivalently, polyhexes where two polyhexes are considered equivalent if and only if they are related by a translation or a rotation of order 3.
REFERENCES
Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Sections 6.2 and 9.4.
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Joseph Myers, Oct 16 2011
STATUS
approved