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A128788
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a(n) = n^2*9^n.
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1
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0, 9, 324, 6561, 104976, 1476225, 19131876, 234365481, 2754990144, 31381059609, 348678440100, 3797108212689, 40669853253264, 429575324987601, 4483851321172356, 46325504721296025, 474373168346071296
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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MATHEMATICA
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CoefficientList[Series[9 x (1 + 9 x)/(1 - 9 x)^3, {x, 0, 30}], x] (* or *) LinearRecurrence[{27, -243, 729}, {0, 9, 324}, 20] (* Vincenzo Librandi, Feb 07 2013 *)
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PROG
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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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