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A239670
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Expansion of 1/((1-x)*(1-81*x)).
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1
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1, 82, 6643, 538084, 43584805, 3530369206, 285959905687, 23162752360648, 1876182941212489, 151970818238211610, 12309636277295140411, 997080538460906373292, 80763523615333416236653, 6541845412842006715168894, 529889478440202543928680415
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OFFSET
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0,2
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COMMENTS
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Partial sums of 81^n.
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LINKS
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FORMULA
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G.f.: 1/((1-x)*(1-81*x)).
a(n) = 82*a(n-1) - 81*a(n-2) for n > 1, a(0)=1, a(1)=82.
a(n) = 81*a(n-1) + 1 for n > 0, a(0)=1.
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EXAMPLE
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Base 9................Decimal
1...........................1
101........................82
10101....................6643
1010101................538084
101010101............43584805
10101010101........3530369206
1010101010101....285959905687, etc.
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MATHEMATICA
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CoefficientList[Series[1/((1 - x) (1 - 81 x)), {x, 0, 40}], x] (* Vincenzo Librandi, Mar 24 2014 *)
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PROG
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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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