A173810 (8*10^n-71)/9 for n>0.

1, 81, 881, 8881, 88881, 888881, 8888881, 88888881, 888888881, 8888888881, 88888888881, 888888888881, 8888888888881, 88888888888881, 888888888888881, 8888888888888881, 88888888888888881, 888888888888888881

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..100

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

Formula

a(n) = 10*a(n-1)+71 with n>0, a(0)=-7.

G.f.: x*(1+70*x)/((1-x)*(1-10*x)). - Vincenzo Librandi, Jul 05 2012

a(n) = 11*a(n-1) -10*a(n-2). - Vincenzo Librandi, Jul 05 2012

Maple

A173810:=n->(8*10^n-71)/9; seq(A173810(k), k=1..50); # Wesley Ivan Hurt, Nov 05 2013

Mathematica

CoefficientList[Series[(1+70*x)/((1-x)*(1-10*x)), {x, 0, 30}], x] (* Vincenzo Librandi, Jul 05 2012
LinearRecurrence[{11, -10}, {1, 81}, 30] (* Harvey P. Dale, Feb 20 2016 *)

Prog

(Magma) [(8*10^n-71)/9: n in [1..20]]; // Vincenzo Librandi, Jul 05 2012

Crossrefs

Cf. A092675.

Sequence in context: A067478 A076749 A222995 * A205047 A086580 A206269

Adjacent sequences: A173807 A173808 A173809 * A173811 A173812 A173813

Keyword

nonn,easy

Author

Vincenzo Librandi, Feb 25 2010

Status

approved