A086946 Numbers k such that R(k+6) = 2.
14, 194, 1994, 19994, 199994, 1999994, 19999994, 199999994, 1999999994, 19999999994, 199999999994, 1999999999994, 19999999999994, 199999999999994, 1999999999999994, 19999999999999994, 199999999999999994, 1999999999999999994, 19999999999999999994, 199999999999999999994
Offset: 1
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..300
- Index entries for linear recurrences with constant coefficients, signature (11,-10).
Programs
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Magma
[2*(10^n-3): n in [1..25] ]; // Vincenzo Librandi, Aug 22 2011
Formula
a(n) = 2*(10^n - 3).
R(a(n)) = A086949(n).
From Stefano Spezia, Dec 15 2022: (Start)
O.g.f.: 2*x*(7 + 20*x)/((1 - x)*(1 - 10*x)).
E.g.f.: 2*(2 - 3*exp(x) + exp(10*x)).
a(n) = 11*a(n-1) - 10*a(n-2) for n > 2. (End)
a(n) = 2*A173833(n). - Elmo R. Oliveira, May 02 2025