A182644 Number of fixed snake polyominoes with n cells.

1, 2, 6, 14, 34, 82, 198, 470, 1122, 2662, 6334, 14970, 35506, 83734, 198086, 466314, 1100818, 2587634, 6097830, 14316402, 33687146, 79008870, 185677006, 435098774, 1021404998, 2391646494, 5609151738, 13125214770, 30757286802, 71928506630

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

Table of n, a(n) for n=1..30.

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).

Sequence in context: A059570 A208902 A018016 * A099425 A186523 A177790

Adjacent sequences: A182641 A182642 A182643 * A182645 A182646 A182647

Keyword

nonn

Author

Joseph Myers, Nov 24 2010

Extensions

More terms from Alain Goupil and Jérôme de Wouters, Jun 21 2014

Status

approved