A199686 a(n) = 6*10^n + 1.

7, 61, 601, 6001, 60001, 600001, 6000001, 60000001, 600000001, 6000000001, 60000000001, 600000000001, 6000000000001, 60000000000001, 600000000000001, 6000000000000001, 60000000000000001, 600000000000000001, 6000000000000000001, 60000000000000000001, 600000000000000000001

Offset

0,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (11,-10).

Formula

a(n) = 10*a(n-1) - 9.

a(n) = 11*a(n-1) - 10*a(n-2).

G.f.: (7-16*x)/((1-x)*(1-10*x)).

E.g.f.: exp(x)*(1 + 6*exp(9*x)). - Elmo R. Oliveira, Jun 10 2025

Mathematica

6*10^Range[0, 20]+1 (* Harvey P. Dale, Oct 23 2024 *)
(* Alternative: *)
LinearRecurrence[{11, -10}, {7, 61}, 20] (* Harvey P. Dale, Oct 23 2024 *)

Prog

(Magma) [6*10^n+1: n in [0..30]];

Crossrefs

Sequence in context: A218473 A098659 A269731 * A390921 A113718 A177132

Adjacent sequences: A199683 A199684 A199685 * A199687 A199688 A199689

Keyword

nonn,easy,changed

Author

Vincenzo Librandi, Nov 09 2011

Status

approved