OFFSET
1,2
COMMENTS
This sequence counts snake polyominoes both with and without holes; for example, it counts all four of these 7-cell snakes:
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LINKS
Alain Goupil, Marie-Eve Pellerin, and Jérôme de Wouters d'Oplinter, Partially Directed Snake Polyominoes, arXiv:1307.8432 [math.CO], 2013-2014.
CROSSREFS
Snake 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).
KEYWORD
nonn
AUTHOR
Joseph Myers, Nov 24 2010
EXTENSIONS
More terms from Alain Goupil and Jérôme de Wouters, Jun 21 2014
STATUS
approved