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A185940
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a(n) = 1 - 2^(n+1) + 3^(n+2).
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1
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24, 74, 228, 698, 2124, 6434, 19428, 58538, 176124, 529394, 1590228, 4774778, 14332524, 43013954, 129074628, 387289418, 1161999324, 3486260114, 10459304628, 31378962458, 94138984524, 282421147874, 847271832228, 2541832273898, 7625530376124, 22876658237234
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OFFSET
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1,1
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LINKS
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FORMULA
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G.f.: 2*x*(12 - 35*x + 24*x^2) / (1 - 6*x + 11*x^2 - 6*x^3)
a(n+2) = -6*a(n) + 5*a(n+1)+2. (End)
a(n) = 6*a(n-1) - 11*a(n-2) + 6*a(n-3). - G. C. Greubel, Feb 25 2017
E.g.f.: exp(x) - 2*exp(2*x) + 9*exp(3*x) - 8. - G. C. Greubel, Jul 23 2017
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MAPLE
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MATHEMATICA
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CoefficientList[Series[-2*x*(12 - 35*x + 24*x^2)/(-1 + 6*x - 11*x^2 + 6*x^3), {x, 0, 50}], x] (* or *) LinearRecurrence[{6, -11, 6}, {24, 74, 228}, 50] (* G. C. Greubel, Feb 25 2017 *)
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PROG
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(PARI) x='x+O('x^50); Vec(-2*x*(12 - 35*x + 24*x^2) / (-1 + 6*x - 11*x^2 + 6*x^3)) \\ G. C. Greubel, Feb 25 2017
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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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