OFFSET
0,2
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (1,-9).
FORMULA
G.f.: (1+2*x)/(1-x+9*x^2).
a(n) = Sum_{k=0..n} A133607(n,k)*3^k. - Philippe Deléham, Dec 29 2007
MATHEMATICA
LinearRecurrence[{1, -9}, {1, 3}, 40] (* Harvey P. Dale, Apr 21 2019 *)
PROG
(PARI) Vec((1+2*x)/(1-x+9*x^2) + O(x^30)) \\ Jinyuan Wang, Apr 09 2020
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Philippe Deléham, Dec 28 2007
EXTENSIONS
Corrected and extended by Harvey P. Dale, Apr 21 2019
STATUS
approved