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A165748
a(n) = (8/9)*(2+7*(-8)^(n-1)).
2
1, 8, -48, 400, -3184, 25488, -203888, 1631120, -13048944, 104391568, -835132528, 6681060240, -53448481904, 427587855248, -3420702841968, 27365622735760, -218924981886064, 1751399855088528, -14011198840708208
OFFSET
0,2
FORMULA
a(n) = (-8)*a(n-1) + 16 for n>=1, with a(0) = 1.
a(n) = 8*a(n-2) - 7*a(n-1), a(0)=1, a(1)=8.
G.f.: (1+15x)/(1+7x-8x^2).
a(n) = Sum_{0<=k<=n} A112555(n,k)*7^(n-k).
From G. C. Greubel, Apr 07 2016: (Start)
a(n) = -7*a(n-1) + 8*a(n-2).
E.g.f.: (1/9)*(16*exp(x) - 7*exp(-8*x)). (End)
MATHEMATICA
Table[(8/9)*(2 + 7*(-8)^(n - 1)), {n, 0, 100}] or
LinearRecurrence[{-7, 8}, {1, 8}, 100] (* G. C. Greubel, Apr 07 2016 *)
PROG
(PARI) x='x+O('x^99); Vec((1+15*x)/(1+7*x-8*x^2)) \\ Altug Alkan, Apr 07 2016
CROSSREFS
Sequence in context: A165049 A013186 A165506 * A220174 A239888 A072169
KEYWORD
easy,sign
AUTHOR
Philippe Deléham, Sep 26 2009
STATUS
approved