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A165510
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a(0)=1, a(1)=9, a(n) = 72*a(n-2) - a(n-1).
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2
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1, 9, 63, 585, 3951, 38169, 246303, 2501865, 15231951, 164902329, 931798143, 10941169545, 56148296751, 731615910489, 3311061455583, 49365284099625, 189031140702351, 3365269314470649, 10244972816098623, 232054417825788105
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OFFSET
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0,2
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COMMENTS
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a(n)/a(n-1) tends to -9.
First term < 0: a(27) = -60053864762402471338497.
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LINKS
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FORMULA
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G.f.: (1+10*x)/(1+x-72*x^2).
a(n) = Sum_{k=0..n} A112555(n,k)*8^k.
E.g.f.: (18*exp(8*x) - exp(-9*x))/17. - G. C. Greubel, Oct 21 2018
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MATHEMATICA
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LinearRecurrence[{-1, 72}, {1, 9}, 30] (* Harvey P. Dale, Oct 15 2012 *)
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PROG
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(PARI) vector(30, n, n--; (18*8^n-(-9)^n)/17) \\ G. C. Greubel, Oct 21 2018
(Magma) [(18*8^n-(-9)^n)/17: n in [0..30]]; // G. C. Greubel, Oct 21 2018
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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