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A151526
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Number of strip poly-IH64-tiles (holes allowed) with n cells.
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4
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1, 2, 4, 8, 19, 43, 103, 239, 569, 1339, 3185, 7503, 17794, 41908, 99137, 233251, 550624, 1294032, 3049412, 7158698, 16844717, 39505579, 92841149
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OFFSET
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1,2
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COMMENTS
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Equivalently, strip polyominoes where two polyominoes are considered the same if and only if they are related by a translation or a reflection in a horizontal line. Formerly described as one-sided strip polyrects, but that is A151523.
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REFERENCES
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Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Sections 6.2 and 9.4.
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LINKS
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CROSSREFS
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Strip polyominoes by group of symmetries relating shapes considered the same: A002013 (all symmetries), A182644 (translations only), A151514 (rotations and translations), A151527 (horizontal and vertical reflections, rotations of order 2 and translations), A151524 (reflections in either diagonal, rotations of order 2 and translations), A151523 (rotations of order 2 and translations), A151526 (reflections in a horizontal line and translations), A182646 (reflections in a NE-SW diagonal line and translations)
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KEYWORD
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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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