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Search: id:A156228
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| A156228 |
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Number of lakes in Conway's Game of Life with 8n cells. |
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+0
1
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| 1, 0, 1, 1, 4, 7, 31, 98, 446, 1894, 9049, 43151
(list; graph; listen)
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OFFSET
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1,5
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COMMENT
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a(n) is also the number of walks on a 2D lattice with the properties that: it turns 90 degrees after every step of length 1, it is a closed loop (ie. it ends where it started) and it never crosses itself.
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LINKS
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N. Johnston, Counting Lakes
LifeWiki, Lakes
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EXAMPLE
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a(2) = 0 because there are no lakes with 16 cells.
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CROSSREFS
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Cf. A019473
Sequence in context: A080871 A102666 A123801 this_sequence A000289 A149089 A004031
Adjacent sequences: A156225 A156226 A156227 this_sequence A156229 A156230 A156231
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KEYWORD
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hard,more,nonn
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AUTHOR
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Nathaniel Johnston (nathaniel(AT)nathanieljohnston.com), Feb 06 2009
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EXTENSIONS
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a(11) and a(12) added by Nathaniel Johnston (nathaniel(AT)nathanieljohnston.com), Mar 09 2009
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