OFFSET
0,2
LINKS
FORMULA
G.f.: (1+3x)/(1-3x-9x^2)=1/(-3x-1/(-3x-1)).
a(n) = (1/2+3*sqrt(5)/10)*(3/2+3*sqrt(5)/2)^n+(1/2-3*sqrt(5)/10)*(3/2-3*sqrt(5)/2)^n.
MATHEMATICA
Table[3^n Fibonacci[n+2], {n, 0, 30}] (* or *) LinearRecurrence[{3, 9}, {1, 6}, 30] (* Harvey P. Dale, May 23 2014 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Mar 24 2010
STATUS
approved