OFFSET
1,6
COMMENTS
Polyiamonds with an odd number of cells have different numbers of triangles with the two orientations and so cannot tile by translation.
REFERENCES
Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Section 9.4.
LINKS
Joseph Myers, Polyiamond tiling
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Joseph Myers, Sep 08 2002
EXTENSIONS
More terms from Joseph Myers, Nov 11 2003
a(15) (30-iamonds) from Joseph Myers, Nov 21 2010
STATUS
approved