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A182467
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a(n) = 3a(n-1) - 2a(n-2) with a(0)=36 and a(1)=90.
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7
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36, 90, 198, 414, 846, 1710, 3438, 6894, 13806, 27630, 55278, 110574, 221166, 442350, 884718, 1769454, 3538926, 7077870, 14155758, 28311534, 56623086, 113246190, 226492398, 452984814, 905969646, 1811939310, 3623878638, 7247757294, 14495514606, 28991029230
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OFFSET
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0,1
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COMMENTS
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Number of vertices into building blocks of 3d objects with 9 vertices.
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LINKS
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FORMULA
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a(n) = a(n-1)*2 + 18
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EXAMPLE
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a(0) = 9+18+9;
a(1) = 9+18+36+18+9;
a(2) = 9+18+36+72+36+18+9;
a(3) = 9+18+36+72+144+72+36+18+9.
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MATHEMATICA
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LinearRecurrence[{3, -2}, {36, 90}, 30] (* or *) CoefficientList[Series[(-18(x-2))/(1-3x+2x^2), {x, 0, 30}], x] (* Harvey P. Dale, Apr 29 2013 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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