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A068931
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Number of incongruent ways to tile a 6 X n room with 1x2 Tatami mats. At most 3 Tatami mats may meet at a point.
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2
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1, 6, 2, 2, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 4, 4, 4, 4, 5, 6, 7, 7, 8, 8, 10, 12, 13, 14, 15, 17, 20, 21, 26, 26, 31, 34, 38, 44, 47, 56, 60, 66, 78, 82, 100, 104, 122, 134, 148, 176, 186, 217, 238, 266, 310, 328, 393, 417, 483, 543, 594, 694, 745, 870, 960, 1066, 1237
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OFFSET
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1,2
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LINKS
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FORMULA
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For n >= 28, a(n) = a(n-5) + a(n-7) + a(n-10) + a(n-14) - a(n-15) - a(n-17) - a(n-19) - a(n-21).
G.f.: -x*(-1-6*x-2*x^2-3*x^16+6*x^15 +2*x^14-6*x^18 +2*x^7+7*x^8+2*x^9 +2*x^10 +6*x^11 +2*x^12+2*x^13-2*x^19-5*x^20-2*x^21 -6*x^22-2*x^23 +x^26 -2*x^3-x^4 +5*x^6)/ ((x^2-x+1) * (x^5+x^4+x^3-x-1) * (x^4-x^2+1) * (x^10 +x^8 +x^6-x^2-1)). - Maksym Voznyy (voznyy(AT)mail.ru), Aug 11 2009; checked and corrected by R. J. Mathar, Sep 16 2009
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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