login
A173391
a(n) = 6n + 3^n.
0
9, 21, 45, 105, 273, 765, 2229, 6609, 19737, 59109, 177213, 531513, 1594401, 4783053, 14348997, 43046817, 129140265, 387420597, 1162261581, 3486784521, 10460353329, 31381059741, 94143178965, 282429536625, 847288609593
OFFSET
1,1
FORMULA
From R. J. Mathar, Feb 21 2010: (Start)
a(n) = 5*a(n-1) - 7*a(n-2) + 3*a(n-3).
G.f.: -3*x*(3-8*x+x^2)/((3*x-1) * (x-1)^2). (End)
PROG
(Magma) [6*n+3^n: n in [1..500]] // Vincenzo Librandi, Dec 04 2010
CROSSREFS
Sequence in context: A135187 A246318 A277715 * A259243 A241747 A133762
KEYWORD
nonn
AUTHOR
Mickel Tolbert (princess_rockstar34(AT)yahoo.com), Feb 17 2010
EXTENSIONS
Extended by R. J. Mathar and Vincenzo Librandi, Feb 21 2010
STATUS
approved