A173736 a(n) = (10^n + 35)/9 for n>0.

5, 15, 115, 1115, 11115, 111115, 1111115, 11111115, 111111115, 1111111115, 11111111115, 111111111115, 1111111111115, 11111111111115, 111111111111115, 1111111111111115, 11111111111111115, 111111111111111115, 1111111111111111115, 11111111111111111115, 111111111111111111115

Offset

1,1

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) = a(n-1) + 10^(n-1) = 10*a(n-1) - 35 with n>0, a(0)=4.

From Vincenzo Librandi, Jul 05 2012: (Start)

G.f.: 5*x*(1-8*x)/((1-x)*(1-10*x)).

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

From Elmo R. Oliveira, Jun 18 2025: (Start)

E.g.f.: -4 + exp(x)*(35 + exp(9*x))/9.

a(n) = 5*A093135(n-1). (End)

Mathematica

CoefficientList[Series[(5-40*x)/((1-x)*(1-10*x)), {x, 0, 30}], x] (* Vincenzo Librandi, Jul 05 2012 *)

Prog

(Magma) [(10^n+35)/9: n in [1..20]]; // Vincenzo Librandi, Jul 05 2012

Crossrefs

Cf. A093135.

Sequence in context: A080490 A220825 A303230 * A244298 A050542 A091096

Adjacent sequences: A173733 A173734 A173735 * A173737 A173738 A173739

Keyword

nonn,easy

Author

Vincenzo Librandi, Feb 23 2010

Status

approved