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A179555
a(1)=10; a(n) = a(n-1)*10 - 1.
1
10, 99, 989, 9889, 98889, 988889, 9888889, 98888889, 988888889, 9888888889, 98888888889, 988888888889, 9888888888889, 98888888888889, 988888888888889, 9888888888888889, 98888888888888889, 988888888888888889, 9888888888888888889, 98888888888888888889
OFFSET
1,1
COMMENTS
For n -> oo, a(n)/10^n -> 0.9888......8889 = 89/90.
FORMULA
From Colin Barker, Oct 03 2015: (Start)
a(n) = 11*a(n-1) - 10*a(n-2) for n>2.
G.f.: -x*(11*x-10) / ((x-1)*(10*x-1)).
(End)
MATHEMATICA
a[1] := 10; a[n_] := a[n] = 10 a[n - 1] - 1; Array[a@ # &, {20}] (* Michael De Vlieger, Oct 03 2015 *)
PROG
(PARI) Vec(-x*(11*x-10)/((x-1)*(10*x-1)) + O(x^30)) \\ Colin Barker, Oct 03 2015
CROSSREFS
Sequence in context: A179558 A179556 A179477 * A105694 A179557 A300000
KEYWORD
nonn,easy
AUTHOR
Mark Dols, Jul 19 2010
EXTENSIONS
Name edited by Colin Barker, Oct 03 2015
STATUS
approved