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A236583
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The number of tilings of an 8 X (3n) floor with 2 X 3 hexominoes.
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1
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1, 1, 4, 11, 33, 96, 281, 821, 2400, 7015, 20505, 59936, 175193, 512089, 1496836, 4375251, 12788857, 37381824, 109267057, 319387565, 933569728, 2728823951, 7976351345, 23314871872, 68149361393
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OFFSET
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0,3
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COMMENTS
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Tilings are counted irrespective of internal symmetry: Tilings that match each other after rotations and/or reflections are counted with their multiplicity.
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LINKS
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FORMULA
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G.f.: (-1+x)^2/(x^3-x^4+1-3*x).
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MAPLE
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g := (-1+x)^2/(x^3-x^4+1-3*x) ;
taylor(%, x=0, 30) ;
gfun[seriestolist](%) ;
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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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