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A165752
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a(n) = (8-5*4^n)/3.
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2
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1, -4, -24, -104, -424, -1704, -6824, -27304, -109224, -436904, -1747624, -6990504, -27962024, -111848104, -447392424, -1789569704, -7158278824, -28633115304, -114532461224, -458129844904, -1832519379624, -7330077518504
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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) = 4*a(n-1) - 8, a(0)=1.
a(n) = 5*a(n-1) - 4*a(n-2), a(0)=1, a(1)=-4, for n>1.
G.f.: (1-9x)/(1-5x+4x^2).
a(n) = Sum_{0<=k<=n} A112555(n,k)*(-5)^(n-k).
E.g.f.: (1/3)*(8*exp(x) - 5*exp(4*x)). - G. C. Greubel, Apr 07 2016
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MATHEMATICA
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(8-5*4^Range[0, 30])/3 (* or *) LinearRecurrence[{5, -4}, {1, -4}, 30] (* Harvey P. Dale, Jan 10 2016 *)
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PROG
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(PARI) x='x+O('x^99); Vec((1-9*x)/(1-5*x+4*x^2)) \\ Altug Alkan, Apr 07 2016
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CROSSREFS
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KEYWORD
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easy,sign
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AUTHOR
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STATUS
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approved
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