A182646 Number of strip poly-IH68-tiles (holes allowed) with n cells.

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.

Links

Table of n, a(n) for n=1..23.

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

Adjacent sequences: A182643 A182644 A182645 * A182647 A182648 A182649

Keyword

nonn

Author

Joseph Myers, Nov 24 2010

Status

approved