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A016306
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Expansion of 1/((1-2*x)*(1-6*x)*(1-9*x)).
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1
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1, 17, 205, 2165, 21421, 204437, 1909885, 17608805, 160998541, 1464103157, 13267627165, 119952839045, 1082840722861, 9765157542677, 88003964122045, 792740954558885, 7138900255858381, 64275492291826997
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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..500
Index entries for linear recurrences with constant coefficients, signature (17,-84,108).
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FORMULA
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G.f.: 1/((1-2*x)*(1-6*x)*(1-9*x)).
From Vincenzo Librandi, Sep 01 2011: (Start)
a(n) = (2^n - 21*6^n + 27*9^n)/7.
a(n) = 17*a(n-1) - 84*a(n-2) + 108*a(n-3) for n > 2.
a(n) = 15*a(n-1) - 54*a(n-2) + 2^n. (End)
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MATHEMATICA
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CoefficientList[Series[1/((1-2x)(1-6x)(1-9x)), {x, 0, 30}], x] (* or *) LinearRecurrence[{17, -84, 108}, {1, 17, 205}, 30] (* Harvey P. Dale, Jan 19 2019 *)
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PROG
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(MAGMA) [(2^n-21*6^n+27*9^n)/7: n in [0..20]]; // Vincenzo Librandi, Sep 01 2011
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CROSSREFS
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Sequence in context: A017897 A016311 A140961 * A021092 A219124 A246989
Adjacent sequences: A016303 A016304 A016305 * A016307 A016308 A016309
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KEYWORD
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nonn,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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