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A199030
a(n) = 10*11^n-1.
2
9, 109, 1209, 13309, 146409, 1610509, 17715609, 194871709, 2143588809, 23579476909, 259374246009, 2853116706109, 31384283767209, 345227121439309, 3797498335832409, 41772481694156509, 459497298635721609, 5054470284992937709
OFFSET
0,1
FORMULA
a(n) = 11*a(n-1)+10.
a(n) = 12*a(n-1)-11*a(n-2).
G.f.: (9+x)/((1-x)*(1-11*x)). - Bruno Berselli, Nov 03 2011
PROG
(Magma) [10*11^n-1: n in [0..20]];
CROSSREFS
Sequence in context: A058421 A267795 A128876 * A288692 A358601 A349335
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Nov 03 2011
STATUS
approved