A075858 n followed by n 1's.

11, 211, 3111, 41111, 511111, 6111111, 71111111, 811111111, 9111111111, 101111111111, 1111111111111, 12111111111111, 131111111111111, 1411111111111111, 15111111111111111, 161111111111111111, 1711111111111111111, 18111111111111111111, 191111111111111111111

Offset

1,1

References

J. Earls, On Smarandache Repunit N Numbers, Smarandache Notions Journal (2004), Vol. 14.1, pp 251-258.

Links

Table of n, a(n) for n=1..19.

Formula

a(n) = n*10^n+(10^n-1)/9.

G.f.: x*(11-20*x)/((1-x)*(1-20*x+100*x^2)). a(n)=20*a(n-1)-100*a(n-2)-9, n>1. - Michael Somos, Oct 29, 2002

Maple

A075858:=n->n*10^n+(10^n-1)/9; seq(A075858(n), n=1..50); # Wesley Ivan Hurt, Nov 23 2013

Mathematica

Table[n*10^n+(10^n-1)/9, {n, 50}] (* Wesley Ivan Hurt, Nov 23 2013 *)

Prog

(PARI) a(n)=if(n<1, 0, n*10^n+(10^n-1)/9)

Crossrefs

Cf. A068817.

Sequence in context: A068836 A069628 A069613 * A136307 A249604 A038399

Adjacent sequences: A075855 A075856 A075857 * A075859 A075860 A075861

Keyword

easy,nonn,less

Author

Jason Earls, Oct 15 2002

Status

approved