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A159617
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G.f.: (1-x)/(1-8*x-8*x^2+8*x^3).
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2
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1, 7, 64, 560, 4936, 43456, 382656, 3369408, 29668864, 261244928, 2300355072, 20255449088, 178356473856, 1570492542976, 13828748541952, 121767076888576, 1072202663100416, 9441127931576320, 83132508142305280, 732011467286249472
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OFFSET
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0,2
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COMMENTS
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Number of tilings of a 2xn board with squares of 2 colors and dominoes of 2 colors if n>2. The number of tilings is 6 if n=1, and 56 if n=2.
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 0..1000
M. Katz, C. Stenson, Tiling a 2xn-board with squares and dominoes, J. Int. Seq. 12 (2009) # 09.2.2
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MATHEMATICA
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CoefficientList[Series[(1 - x)/(1 - 8 x - 8 x^2 + 8 x^3), {x, 0, 40}], x] (* Vincenzo Librandi, Dec 11 2012 *)
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CROSSREFS
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Cf. A030186, A102436, A159616.
Sequence in context: A136955 A027767 A055537 * A098307 A055995 A213515
Adjacent sequences: A159614 A159615 A159616 * A159618 A159619 A159620
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KEYWORD
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nonn,easy
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AUTHOR
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R. J. Mathar, Apr 17 2009
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STATUS
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approved
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