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Search: id:A068927
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| A068927 |
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Number of incongruent ways to tile a 2 X n room with 1x2 Tatami mats. At most 3 Tatami mats may meet at a point. |
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+0
4
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| 1, 1, 2, 3, 4, 6, 8, 12, 16, 24, 33, 49, 69, 102, 145, 214, 307, 452, 653, 960, 1393, 2046, 2978, 4371, 6376, 9354, 13665, 20041, 29307, 42972, 62884, 92191, 134974, 197858, 289772, 424746, 622198, 911970, 1336121, 1958319, 2869417, 4205538
(list; graph; listen)
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OFFSET
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1,3
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FORMULA
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For n >= 12, a(n) = a(n-1) + a(n-2) - a(n-5) + a(n-6) - a(n-7) - a(n-9).
G.f.: x*(1-x^10-2*x^8-2*x^6-x^4) / ((x^3+x-1) * (x^6+x^2-1)) [From Maksym Voznyy (voznyy(AT)mail.ru), Aug 11 2009]
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CROSSREFS
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Cf. A068921 for total number of tilings, A068926 for more info.
Sequence in context: A018425 A018328 A018280 this_sequence A018261 A018438 A107368
Adjacent sequences: A068924 A068925 A068926 this_sequence A068928 A068929 A068930
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KEYWORD
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easy,nonn
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AUTHOR
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Dean Hickerson (dean.hickerson(AT)yahoo.com), Mar 11 2002
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EXTENSIONS
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G.f. proposed by Maksym Voznyy checked and corrected by R. J. Mathar, Sep 16 2009.
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