OFFSET
0,2
LINKS
FORMULA
G.f.: (1+8*x)/(1-x+81*x^2).
a(n) = Sum_{k=0..n} A133607(n,k)*9^k. - Philippe Deléham, Dec 30 2007
MATHEMATICA
LinearRecurrence[{1, -81}, {1, 9}, 30] (* Harvey P. Dale, Aug 01 2016 *)
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Philippe Deléham, Dec 29 2007
STATUS
approved