

A165752


a(n) = (85*4^n)/3.


2



1, 4, 24, 104, 424, 1704, 6824, 27304, 109224, 436904, 1747624, 6990504, 27962024, 111848104, 447392424, 1789569704, 7158278824, 28633115304, 114532461224, 458129844904, 1832519379624, 7330077518504
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OFFSET

0,2


LINKS

G. C. Greubel, Table of n, a(n) for n = 0..500
Index entries for linear recurrences with constant coefficients, signature (5,4).


FORMULA

a(n) = 4*a(n1)  8, a(0)=1.
a(n) = 5*a(n1)  4*a(n2), a(0)=1, a(1)=4, for n>1.
G.f.: (19x)/(15x+4x^2).
a(n) = Sum_{0<=k<=n} A112555(n,k)*(5)^(nk).
a(n) = (4)*A020989(n1).
E.g.f.: (1/3)*(8*exp(x)  5*exp(4*x)).  G. C. Greubel, Apr 07 2016


MATHEMATICA

(85*4^Range[0, 30])/3 (* or *) LinearRecurrence[{5, 4}, {1, 4}, 30] (* Harvey P. Dale, Jan 10 2016 *)


PROG

(PARI) x='x+O('x^99); Vec((19*x)/(15*x+4*x^2)) \\ Altug Alkan, Apr 07 2016


CROSSREFS

Sequence in context: A048806 A043009 A006736 * A166036 A120908 A145655
Adjacent sequences: A165749 A165750 A165751 * A165753 A165754 A165755


KEYWORD

easy,sign


AUTHOR

Philippe Deléham, Sep 26 2009


STATUS

approved



