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A182644
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Number of fixed snake polyominoes with n cells.
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5
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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
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OFFSET
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1,2
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COMMENTS
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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
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CROSSREFS
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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).
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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