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A024103
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a(n) = 9^n - n^2.
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2
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1, 8, 77, 720, 6545, 59024, 531405, 4782920, 43046657, 387420408, 3486784301, 31381059488, 282429536337, 2541865828160, 22876792454765, 205891132094424, 1853020188851585, 16677181699666280, 150094635296998797
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = 12*a(n-1) -30*a(n-2) +28*a(n-3) -9*a(n-4) for n>3. - Vincenzo Librandi, Oct 06 2014
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MATHEMATICA
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Table[9^n - n^2, {n, 0, 25}] (* or *) CoefficientList[Series[(1 - 4 x + 11 x^2 + 8 x^3)/((1 - 9 x) (1 - x)^3), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 06 2014 *)
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PROG
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CROSSREFS
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Cf. similar sequences listed in A024025.
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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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