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A034513
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a(n) = 1^n + 3^n + 9^n.
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88
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3, 13, 91, 757, 6643, 59293, 532171, 4785157, 43053283, 387440173, 3486843451, 31381236757, 282430067923, 2541867422653, 22876797237931, 205891146443557, 1853020231898563, 16677181828806733, 150094635684419611
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OFFSET
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0,1
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COMMENTS
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Also the sum of n-th powers of the divisors of 9.
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LINKS
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FORMULA
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G.f.: 1/(1-x)+1/(1-3*x)+1/(1-9*x). E.g.f.: e^x+e^(3*x)+e^(9*x). - Mohammad K. Azarian, Dec 26 2008
a(n) = 13*a(n-1) - 39*a(n-2) + 27*a(n-3), a(0)=3, a(1)=13, a(2)=91. - Harvey P. Dale, Apr 13 2012
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MATHEMATICA
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Table[1^n + 3^n + 9^n, {n, 0, 20}]
LinearRecurrence[{13, -39, 27}, {3, 13, 91}, 20] (* Harvey P. Dale, Apr 13 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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