A173802 a(n)=(5*10^n-23)/9.

3, 53, 553, 5553, 55553, 555553, 5555553, 55555553, 555555553, 5555555553, 55555555553, 555555555553, 5555555555553, 55555555555553, 555555555555553, 5555555555555553, 55555555555555553, 555555555555555553

Offset

1,1

Links

Table of n, a(n) for n=1..18.

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

Formula

a(n)=10*a(n-1)+23, n>1.

G.f. x*(3+20*x) / ( (10*x-1)*(x-1) ). - R. J. Mathar, Aug 24 2011

Example

For n=2, a(2)=10*3+23=53; n=3, a(3)=10*53+23=553; n=4, a(4)=10*553+23=5553

Mathematica

Rest[CoefficientList[Series[x*(3 + 20*x)/((10*x - 1)*(x - 1)), {x, 0, 50}], x]] (* G. C. Greubel, May 06 2017 *)
Table[FromDigits[PadLeft[{3}, n, 5]], {n, 20}] (* or *) LinearRecurrence[ {11, -10}, {3, 53}, 20] (* Harvey P. Dale, May 27 2018 *)

Prog

(PARI) x=x+O('x^50); Vec(x*(3+20*x)/((10*x-1)*(x-1))) \\ G. C. Greubel, May 06 2017

Crossrefs

Cf. A093164.

Sequence in context: A215435 A121504 A099665 * A001279 A092447 A167217

Adjacent sequences: A173799 A173800 A173801 * A173803 A173804 A173805

Keyword

nonn,easy

Author

Vincenzo Librandi, Feb 25 2010

Status

approved