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A016312
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Expansion of 1/((1-2x)*(1-7x)*(1-9x)).
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1
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1, 18, 229, 2538, 26197, 259290, 2498293, 23637546, 220808533, 2043771642, 18789409717, 171872944074, 1566234297109, 14231753285274, 129035291862901, 1167964212866922, 10558204018573525, 95349518886691386
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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) = ((9^n - 2^n)/7 - (7^n - 2^n)/5)/2, n >= 2. - Zerinvary Lajos, Jun 05 2009
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MATHEMATICA
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CoefficientList[Series[1 / ((1 - 2 x) (1 - 7 x) (1 - 9 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jun 26 2013 *)
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PROG
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(Sage) [((9^n - 2^n)/7-(7^n - 2^n)/5)/2 for n in range(2, 20)] # Zerinvary Lajos, Jun 05 2009
(Magma) I:=[1, 18, 229]; [n le 3 select I[n] else 18*Self(n-1)-95*Self(n-2)+126*Self(n-3): n in [1..20]]; /* or */ m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-2*x)*(1-7*x)*(1-9*x)))); // Vincenzo Librandi, Jun 26 2013
(PARI) x='x+O('x^99); Vec(1/((1-2*x)*(1-7*x)*(1-9*x))) \\ Altug Alkan, Sep 21 2018
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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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