A098406 a(n) = (10^n + 17)/9.

2, 3, 13, 113, 1113, 11113, 111113, 1111113, 11111113, 111111113, 1111111113, 11111111113, 111111111113, 1111111111113, 11111111111113, 111111111111113, 1111111111111113, 11111111111111113, 111111111111111113

Offset

0,1

Comments

A097683 gives numbers k such that a(k) is prime.

a(n) = A047855(n)+1 = A002275(n)+2.

Links

Ivan Panchenko, Table of n, a(n) for n = 0..200

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

Formula

a(1) = 3; a(n) = a(n-1)+10^(n-1).

a(1) = 3; a(n) = 10*a(n-1)-17.

G.f.: ( 2-19*x ) / ( (10*x-1)*(x-1) ). - R. J. Mathar, Jan 27 2017

Example

a(5) = (100000+17)/9 = 11113.

Mathematica

FromDigits/@Table[PadLeft[{3}, n, 1], {n, 20}] (* Harvey P. Dale, Jun 18 2011 *)

Prog

(PARI) for(n=1, 18, print1(((10^n)+17)/9, ", "))

Crossrefs

Cf. A097683, A047855, A002275.

Sequence in context: A068096 A098462 A125283 * A280012 A224792 A062447

Adjacent sequences: A098403 A098404 A098405 * A098407 A098408 A098409

Keyword

nonn,easy

Author

Klaus Brockhaus, Sep 07 2004

Extensions

a(0) from Ivan Panchenko, Nov 02 2013

Status

approved