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A074554
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a(n) = 3^n + 5^n + 9^n.
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1
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3, 17, 115, 881, 7267, 62417, 547795, 4863281, 43443907, 389393297, 3496609075, 31430064881, 282674208547, 2543088125777, 22882900753555, 205921664021681, 1853172819789187, 16677944768259857, 150098450381685235
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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/(1-3*x) + 1/(1-5*x) + 1/(1-9*x).
E.g.f.: exp(3*x) + exp(5*x) + exp(9*x). (End)
a(n) = 17*a(n-1) - 87*a(n-2) + 135*a(n-3).
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MATHEMATICA
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Table[3^n + 5^n + 9^n, {n, 0, 20}]
LinearRecurrence[{17, -87, 135}, {3, 17, 115}, 30] (* Harvey P. Dale, Nov 27 2012 *)
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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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