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A151526
Number of strip poly-IH64-tiles (holes allowed) with n cells.
4
1, 2, 4, 8, 19, 43, 103, 239, 569, 1339, 3185, 7503, 17794, 41908, 99137, 233251, 550624, 1294032, 3049412, 7158698, 16844717, 39505579, 92841149
OFFSET
1,2
COMMENTS
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.
REFERENCES
Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Sections 6.2 and 9.4.
CROSSREFS
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)
Sequence in context: A261663 A199694 A037444 * A099526 A005703 A172383
KEYWORD
nonn
AUTHOR
Ed Pegg Jr, May 13 2009
EXTENSIONS
Edited and a(15)-a(23) by Joseph Myers, Nov 24 2010
STATUS
approved