OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..998
Index entries for linear recurrences with constant coefficients, signature (9,9).
FORMULA
G.f.: (1-x-x^2)/(1-9*x-9*x^2).
From G. C. Greubel, Mar 24 2021: (Start)
a(n) = (1/9)*[n=0] - 8*3^(n-2)*ChebyshevU(n, -3*i/2).
a(n) = (1/9)*[n=0] + 8*3^(n-2)*Fibonacci(n+1, 3). (End)
MAPLE
m:=30; S:=series( (1-x-x^2)/(1-9*x-9*x^2), x, m+1):
seq(coeff(S, x, j), j=0..m); # G. C. Greubel, Mar 24 2021
MATHEMATICA
Join[{1}, LinearRecurrence[{9, 9}, {8, 80}, 20]] (* or *) CoefficientList[ Series[ (1-x-x^2)/(1-9x-9x^2), {x, 0, 20}], x] (* Harvey P. Dale, Jun 19 2011 *)
PROG
(Magma) [1] cat [n le 2 select 8*(9*n-8) else 9*(Self(n-1) + Self(n-2)): n in [1..30]]; // G. C. Greubel, Mar 24 2021
(Sage) [1]+[-8*(3*i)^(n-2)*chebyshev_U(n, -3*i/2) for n in (1..30)] # G. C. Greubel, Mar 24 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Philippe Deléham, Jan 21 2009
STATUS
approved