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A075221
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Number of polyiamonds with n cells that tile the plane by translation or by 180-degree rotation (Conway criterion).
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10
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1, 1, 1, 3, 4, 12, 21, 56, 111, 262, 462, 1453, 1875, 4734, 9410, 20603, 24034, 79352, 79925, 273731, 358096, 669640, 796571, 3342349, 2980476, 6387513, 10167660, 24999509, 21477012, 87978317
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listen;
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OFFSET
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1,4
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REFERENCES
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Branko Grünbaum 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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CROSSREFS
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Cf. A071332, A075216, A075217, A075218, A075219, A075220, A075222, A075223, A075224, A075203, A075212.
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KEYWORD
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hard,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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