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A173806
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a(n) = (7*10^n-61)/9 for n>0.
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2
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1, 71, 771, 7771, 77771, 777771, 7777771, 77777771, 777777771, 7777777771, 77777777771, 777777777771, 7777777777771, 77777777777771, 777777777777771, 7777777777777771, 77777777777777771, 777777777777777771
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) = 10*a(n-1)+61 with n>0, a(0)=-6.
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MATHEMATICA
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CoefficientList[Series[(1+60*x)/((1-x)*(1-10*x)), {x, 0, 30}], x] (* Vincenzo Librandi, Jul 05 2012 *)
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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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