A151523 Number of 1-sided strip polyrhombs with n cells.

1, 2, 4, 10, 20, 48, 106, 252, 578, 1372, 3208, 7584, 17850, 42102, 99276, 233716, 550960, 1295146, 3050226, 7161346, 16846668, 39511876, 92845830

Offset: 1

Author

Ed Pegg Jr, May 13 2009

Keywords

• nonn
• hard
• more

Comments

Also counts 1-sided strip polyrects.

Links

• Ed Pegg, Jr., Illustrations of polyforms
• Eric Weisstein's World of Mathematics, Polyrhomb
• Eric Weisstein's World of Mathematics, Polyrect

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)

Extensions

Edited and a(15)-a(23) by Joseph Myers, Nov 24 2010