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Search: id:A075218
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| A075218 |
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Number of polyiamonds with 2n cells that tile the plane both by translation and by 180-degree rotation (Conway criterion). |
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+0
11
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| 1, 2, 8, 24, 61, 269, 501, 2121, 4709, 14978, 26675, 123081, 179707, 660366
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Polyiamonds with an odd number of cells have different numbers of triangles with the two orientations and so cannot tile by translation.
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REFERENCES
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Branko Gruenbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Section 9.4.
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LINKS
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Joseph Myers, Polyiamond tiling
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CROSSREFS
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Cf. A071332, A075216, A075217, A075219, A075220, A075221, A075222, A075223, A075224, A075200, A075209.
Sequence in context: A051745 A006734 A131064 this_sequence A006728 A075216 A127790
Adjacent sequences: A075215 A075216 A075217 this_sequence A075219 A075220 A075221
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KEYWORD
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hard,nonn
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AUTHOR
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Joseph Myers (jsm(AT)polyomino.org.uk), Sep 08 2002
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EXTENSIONS
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More terms from Joseph Myers (jsm(AT)polyomino.org.uk), Nov 11 2003
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