A171226 9+10^n+9*100^n.

19, 919, 90109, 9001009, 900010009, 90000100009, 9000001000009, 900000010000009, 90000000100000009, 9000000001000000009, 900000000010000000009, 90000000000100000000009, 9000000000001000000000009, 900000000000010000000000009, 90000000000000100000000000009

Offset

0,1

Links

Table of n, a(n) for n=0..14.

Index entries for linear recurrences with constant coefficients, signature (111, -1110, 1000).

Formula

a(n) = 111*a(n-1) -1110*a(n-2) +1000*a(n-3).

G.f.: -(19-1190*x+9190*x^2)/((x-1) * (100*x-1) * (10*x-1)). - R. J. Mathar, Feb 14 2010

Maple

A171226:=n->9+10^n+9*100^n; seq(A171226(n), n=0..20); # Wesley Ivan Hurt, Mar 07 2014

Mathematica

LinearRecurrence[{111, -1110, 1000}, {19, 919, 90109}, 20] (* Harvey P. Dale, Oct 24 2011 *)

Prog

(PARI) a(n) = 9+10^n+9*100^n; \\ Michel Marcus, Mar 08 2014

Crossrefs

Cf. A083816.

Sequence in context: A209353 A368789 A005535 * A247279 A192569 A238740

Adjacent sequences: A171223 A171224 A171225 * A171227 A171228 A171229

Keyword

easy,nonn

Author

Jason Earls, Dec 05 2009

Status

approved