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A141012
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a(0) = 0, a(n) = 13^(n-1) + 1.
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7
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0, 2, 14, 170, 2198, 28562, 371294, 4826810, 62748518, 815730722, 10604499374, 137858491850, 1792160394038, 23298085122482, 302875106592254, 3937376385699290, 51185893014090758
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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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E.g.f.: Sum_{d|M} (exp(d*x) - 1)/d, M=13.
a(n) = Sum_{d|13} d^(n-1) = 1 + 13^(n-1) = 1 + A001022(n-1), n > 0.
a(n) = 14*a(n-1) - 13*a(n-2), n > 2.
G.f.: -2*x*(-1+7*x)/((13*x-1)*(x-1)). (End)
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MATHEMATICA
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Join[{0}, 13^(#-1)+1&/@Range[20]] (* or *) Join[{0}, LinearRecurrence[ {14, -13}, {2, 14}, 20]] (* Harvey P. Dale, Oct 14 2013 *)
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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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