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A115102
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a(0)=2, a(1)=8, a(n)=a(n-1)+2*a(n-2).
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2
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2, 8, 12, 28, 52, 108, 212, 428, 852, 1708, 3412, 6828, 13652, 27308, 54612, 109228, 218452, 436908, 873812, 1747628, 3495252, 6990508, 13981012, 27962028, 55924052, 111848108, 223696212, 447392428, 894784852, 1789569708, 3579139412, 7158278828
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OFFSET
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0,1
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COMMENTS
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LINKS
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FORMULA
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G.f.: (2+6*x)/( (1+x)*(1-2*x) ).
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MATHEMATICA
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LinearRecurrence[{1, 2}, {2, 8}, 40] (* or *) Table[(4(-1)^x+5*2^x)/3, {x, 40}] (* Harvey P. Dale, Sep 02 2016 *)
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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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EXTENSIONS
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STATUS
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approved
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