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A033569
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(2*n-1)*(3*n+1).
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1
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-1, 4, 21, 50, 91, 144, 209, 286, 375, 476, 589, 714, 851, 1000, 1161, 1334, 1519, 1716, 1925, 2146, 2379, 2624, 2881, 3150, 3431, 3724, 4029, 4346, 4675, 5016, 5369, 5734, 6111, 6500, 6901, 7314, 7739
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OFFSET
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0,2
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for sequences related to linear recurrences with constant coefficients, signature (3,-3,1).
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FORMULA
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G.f.: (-1+7*x+6*x^2)/(1-x)^3. - Vincenzo Librandi, Jul 07 2012
a(n) = 3*a(n-1) -3*a(n-2) +a(n-3). - Vincenzo Librandi, Jul 07 2012
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MATHEMATICA
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CoefficientList[Series[(-1+7*x+6*x^2)/(1-x)^3, {x, 0, 50}], x] (* Vincenzo Librandi, Jul 07 2012 *)
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PROG
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(MAGMA) [(2*n-1)*(3*n+1): n in [0..50]]; // Vincenzo Librandi, Jul 07 2012
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CROSSREFS
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Sequence in context: A063122 A110737 A042223 * A201446 A220772 A135559
Adjacent sequences: A033566 A033567 A033568 * A033570 A033571 A033572
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KEYWORD
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sign,easy
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AUTHOR
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N. J. A. Sloane.
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STATUS
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approved
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