A173833 a(n) = 10^n - 3.
7, 97, 997, 9997, 99997, 999997, 9999997, 99999997, 999999997, 9999999997, 99999999997, 999999999997, 9999999999997, 99999999999997, 999999999999997, 9999999999999997, 99999999999999997, 999999999999999997, 9999999999999999997, 99999999999999999997, 999999999999999999997
Offset: 1
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..100
- Index entries for linear recurrences with constant coefficients, signature (11,-10).
Programs
-
Mathematica
LinearRecurrence[{11, -10}, {7, 97}, 20] (* Vincenzo Librandi, Feb 22 2012 *) -
PARI
a(n)=10^n-3 \\ Charles R Greathouse IV, Jan 11 2012
Formula
a(n) = 10*a(n-1) + 27 with n > 1, a(1)=7.
G.f.: x*(20*x+7)/((x-1)*(10*x-1)). - Colin Barker, Jan 24 2013
E.g.f.: 2 - 3*exp(x) + exp(10*x). - Stefano Spezia, May 02 2025
From Elmo R. Oliveira, May 07 2025: (Start)
a(n) = 11*a(n-1) - 10*a(n-2) for n > 2.
a(n) = A086947(n)/3. (End)