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A253213
a(n) = 10^n + 9.
3
10, 19, 109, 1009, 10009, 100009, 1000009, 10000009, 100000009, 1000000009, 10000000009, 100000000009, 1000000000009, 10000000000009, 100000000000009, 1000000000000009, 10000000000000009, 100000000000000009, 1000000000000000009, 10000000000000000009, 100000000000000000009
OFFSET
0,1
FORMULA
a(n) = 11*a(n-1) - 10*a(n-2) for n > 1.
G.f.: (10 - 91*x)/((1 - x)*(1 - 10*x)).
E.g.f.: exp(x)*(exp(9*x) + 9). - Elmo R. Oliveira, Sep 15 2024
MATHEMATICA
Table[10^n + 9, {n, 0, 40}]
LinearRecurrence[{11, -10}, {10, 19}, 40] (* Harvey P. Dale, Jun 29 2018 *)
PROG
(Magma) [10^n+9: n in [0..30]];
CROSSREFS
Cf. similar sequences listed in A253208.
Cf. A170955.
Sequence in context: A070199 A015445 A220005 * A293929 A177203 A177167
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Dec 30 2014
EXTENSIONS
a(20) from Elmo R. Oliveira, Sep 15 2024
a(20) corrected by Sean A. Irvine, Sep 22 2024
STATUS
approved