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A075222
Number of polyiamonds with n cells that tile the plane isohedrally but not by translation or by 180-degree rotation (Conway criterion).
10
0, 0, 0, 0, 0, 0, 2, 10, 22, 54, 52, 534, 523, 1339, 3218, 9315, 2177, 29426, 15423, 101314, 140072, 110794, 46748, 1639279, 710736, 970251, 3002062, 8462256, 895291, 29458807
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.
KEYWORD
hard,nonn
AUTHOR
Joseph Myers, Sep 08 2002
EXTENSIONS
More terms from Joseph Myers, Nov 11 2003
a(29) and a(30) from Joseph Myers, Nov 21 2010
STATUS
approved