OFFSET
0,1
COMMENTS
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (0,6,0,-1).
FORMULA
G.f.: (2+9*x-x^3)/((x^2+2*x-1)*(x^2-2*x-1)).
From Colin Barker, May 26 2016: (Start)
a(n) = ((-1-sqrt(2))^(1+n)-(-1+sqrt(2))^(1+n)+(1-sqrt(2))^n*(-4+3*sqrt(2))+(1+sqrt(2))^n*(4+3*sqrt(2)))/(2*sqrt(2)).
a(n) = 6*a(n-2)-a(n-4) for n>3.
(End)
MATHEMATICA
CoefficientList[Series[(2 + 9 x - x^3)/((x^2 + 2 x - 1) (x^2 - 2 x - 1)), {x, 0, 29}], x] (* Michael De Vlieger, May 26 2016 *)
PROG
(PARI) Vec((2+9*x-x^3)/((x^2+2*x-1)*(x^2-2*x-1)) + O(x^40)) \\ Colin Barker, May 26 2016
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Creighton Dement, Apr 10 2007
STATUS
approved