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A182646
Number of strip poly-IH68-tiles (holes allowed) with n cells.
4
1, 1, 4, 7, 19, 41, 104, 235, 572, 1331, 3193, 7485, 17811, 41867, 99181, 233157, 550718, 1293817, 3049649, 7158201, 16845217, 39504435, 92842398
OFFSET
1,3
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 NE-SW diagonal line.
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: A140167 A182228 A352007 * A190646 A220011 A305034
KEYWORD
nonn
AUTHOR
Joseph Myers, Nov 24 2010
STATUS
approved