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0, 7, 392, 9261, 153664, 2100875, 25412184, 282475249, 2951578112, 29417779503, 282475249000, 2631821894933, 23917744283328, 212865155864179, 1861044111897656, 16023020096057625, 136122083613085696
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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 linear recurrences with constant coefficients, signature (28,-294,1372,-2401).
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FORMULA
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G.f.: 7*x*(1 + 28*x + 49x^2)/(1 - 7*x)^4. - Vincenzo Librandi, Feb 08 2013
a(n) = 28*a(n-1) - 294*a(n-2) + 1372*a(n-3) - 2401*a(n-4). - Vincenzo Librandi, Feb 09 2013
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MATHEMATICA
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CoefficientList[Series[7*x*(1 + 28*x + 49*x^2)/(1 - 7*x)^4, {x, 0, 40}], x] (* Vincenzo Librandi, Feb 08 2013 *)
Table[n^3 7^n, {n, 0, 20}] (* or *) LinearRecurrence[{28, -294, 1372, -2401}, {0, 7, 392, 9261}, 20] (* Harvey P. Dale, Aug 30 2020 *)
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PROG
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(Magma) [n^3*7^n: n in [0..20]]; // Vincenzo Librandi, Feb 08 2013
(Magma) I:=[0, 7, 392, 9261]; [n le 4 select I[n] else 28*Self(n-1)-294*Self(n-2)+1372*Self(n-3)-2401*Self(n-4): n in [1..30]]; // Vincenzo Librandi, Feb 09 2013
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CROSSREFS
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Cf. A036289, A007758.
Sequence in context: A185354 A222893 A009712 * A042527 A203588 A015022
Adjacent sequences: A128790 A128791 A128792 * A128794 A128795 A128796
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KEYWORD
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nonn,easy
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AUTHOR
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Mohammad K. Azarian, Apr 07 2007
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STATUS
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approved
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