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A074575
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a(n) = 5^n + 7^n + 9^n.
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1
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3, 21, 155, 1197, 9587, 78981, 664715, 5684637, 49202147, 429727221, 3779025275, 33407214477, 296514964307, 2639975541861, 23561119043435, 210669211182717, 1886405707312067, 16910575153106901, 151726863592175195
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OFFSET
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0,1
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LINKS
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FORMULA
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G.f.: 1/(1-5*x) + 1/(1-7*x) + 1/(1-9*x).
E.g.f.: e^(5*x) + e^(7*x) + e^(9*x). (End)
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MATHEMATICA
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Table[5^n + 7^n + 9^n, {n, 0, 20}]
LinearRecurrence[{21, -143, 315}, {3, 21, 155}, 20] (* Harvey P. Dale, Jul 14 2019 *)
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PROG
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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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