

A151522


Number of 1sided polyrhombs with n cells.


3



1, 2, 4, 13, 35, 120, 392, 1405, 4998, 18378, 67792, 253509, 952534, 3604624, 13699554, 52304807, 200406370, 770442286
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


COMMENTS

Also counts 1sided polyrects.


LINKS

Table of n, a(n) for n=1..18.
Ed Pegg, Jr., Illustrations of polyforms
Eric Weisstein's World of Mathematics, Polyrhomb
Eric Weisstein's World of Mathematics, Polyrect


CROSSREFS

Polyominoes by group of symmetries relating shapes considered the same: A000105 (all symmetries), A001168 (translations only), A000988 (rotations and translations), A056780 (horizontal and vertical reflections, rotations of order 2 and translations), A056783 (reflections in either diagonal, rotations of order 2 and translations), A151522 (rotations of order 2 and translations), A151525 (reflections in a horizontal line and translations), A182645 (reflections in a NESW diagonal line and translations)
Sequence in context: A189590 A189597 A148235 * A148236 A148237 A148238
Adjacent sequences: A151519 A151520 A151521 * A151523 A151524 A151525


KEYWORD

nonn,hard,more


AUTHOR

Ed Pegg Jr, May 13 2009


EXTENSIONS

Edited and a(13)a(18) by Joseph Myers, Nov 24 2010


STATUS

approved



