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A098611
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a(n) = 10^n-(-1)^n.
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3
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0, 11, 99, 1001, 9999, 100001, 999999, 10000001, 99999999, 1000000001, 9999999999, 100000000001, 999999999999, 10000000000001, 99999999999999, 1000000000000001, 9999999999999999, 100000000000000001, 999999999999999999, 10000000000000000001
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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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G.f.: 11*x/(1-9*x-10*x^2).
a(n) = 9*a(n-1) + 10*a(n-2). (End)
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MAPLE
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MATHEMATICA
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Table[(10^n - (-1)^n), {n, 0, 30}] (* or *)
CoefficientList[Series[11 x/(1 - 9 x - 10 x^2), {x, 0, 30}], x] (* Wesley Ivan Hurt, Apr 05 2015 *)
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PROG
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(PARI) vector(20, n, 10^(n-1)+(-1)^n) \\ Derek Orr, Apr 05 2015
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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