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(n-1) - 8, a(0)=1.
a(n) = 5*a(n-1) - 4*a(n-2), a(0)=1, a(1)=-4, for n>1.
G.f.: (1-9x)/(1-5x+4x^2).
a(n) = Sum_{0<=k<=n} A112555(n,k)*(-5)^(n-k).
a(n) = (-4)*A020989(n-1).
E.g.f.: (1/3)*(8*exp(x) - 5*exp(4*x)). - G. C. Greubel, Apr 07 2016
MATHEMATICA
(8-5*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((1-9*x)/(1-5*x+4*x^2)) \\ Altug Alkan, Apr 07 2016
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Philippe Deléham, Sep 26 2009
STATUS
approved