A199689 a(n) = 8*10^n + 1.
9, 81, 801, 8001, 80001, 800001, 8000001, 80000001, 800000001, 8000000001, 80000000001, 800000000001, 8000000000001, 80000000000001, 800000000000001, 8000000000000001, 80000000000000001, 800000000000000001, 8000000000000000001, 80000000000000000001, 800000000000000000001
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (11,-10).
Programs
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Magma
[8*10^n+1: n in [0..30]];
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Mathematica
8*10^Range[0,20]+1 (* or *) LinearRecurrence[{11,-10},{9,81},20] (* Harvey P. Dale, Jun 11 2022 *)
Formula
a(n) = 9*A059482(n).
a(n) = 10*a(n-1) - 9.
a(n) = 11*a(n-1) - 10*a(n-2).
G.f.: 9*(1-2*x)/((1-x)*(1-10*x)).
From Elmo R. Oliveira, May 04 2025: (Start)
E.g.f.: exp(x)*(1 + 8*exp(9*x)).
a(n) = 3*A199688(n). (End)