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A199026
7*11^n-1.
1
6, 76, 846, 9316, 102486, 1127356, 12400926, 136410196, 1500512166, 16505633836, 181561972206, 1997181694276, 21968998637046, 241658985007516, 2658248835082686, 29240737185909556, 321648109045005126, 3538129199495056396
OFFSET
0,1
FORMULA
a(n) = 11*a(n-1)+10.
a(n) = 12*a(n-1)-11*a(n-2), n>1.
G.f.: 2*(3 + 2*x)/(1 - 12*x + 11*x^2). - Vincenzo Librandi, Jan 04 2013
MATHEMATICA
7*11^Range[0, 20]-1 (* or *) LinearRecurrence[{12, -11}, {6, 76}, 20] (* Harvey P. Dale, Jun 22 2012 *)
CoefficientList[Series[2*(3 + 2*x)/(1 - 12*x + 11*x^2), {x, 0, 30}], x] (* Vincenzo Librandi, Jan 04 2013 *)
PROG
(Magma) [7*11^n-1 : n in [0..20]]
CROSSREFS
Sequence in context: A241072 A137132 A053337 * A155643 A066797 A333097
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Nov 02 2011
STATUS
approved