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A174634
a(n) = 3^n*F(n+2).
0
1, 6, 27, 135, 648, 3159, 15309, 74358, 360855, 1751787, 8503056, 41275251, 200353257, 972537030, 4720790403, 22915204479, 111232727064, 539935021503, 2620899608085, 12722114017782, 61754438526111, 299762341738371, 1455076971950112, 7063091991495675
OFFSET
0,2
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
Cf. A000045.
Sequence in context: A343492 A323928 A360082 * A377153 A373714 A018901
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Mar 24 2010
STATUS
approved