A063945 Number of nonnegative integers with n digits.

10, 90, 900, 9000, 90000, 900000, 9000000, 90000000, 900000000, 9000000000, 90000000000, 900000000000, 9000000000000, 90000000000000, 900000000000000, 9000000000000000, 90000000000000000, 900000000000000000, 9000000000000000000, 90000000000000000000

Offset: 1

Author

Shyam Sunder Gupta, Sep 01 2001

Keywords

• base
• easy
• nonn

Comments

Also, first differences of A000533. - Omar E. Pol, Feb 24 2011

Links

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

Crossrefs

Column k=1 of A216653.

Programs

Maple

a:= n-> `if`(n=1, 10, 9*10^(n-1)):
seq(a(n), n=1..30);  # Alois P. Heinz, Sep 12 2012

Mathematica

Join[{10},NestList[10#&,90,20]] (* Harvey P. Dale, Dec 31 2022 *)

Formula

a(1) = 10, a(2) = 90, a(n) = a(n-1)*10 for n>2.

a(n) = A052268(n), n>1. - R. J. Mathar, Oct 02 2008

From Stefano Spezia, Dec 01 2024: (Start)

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

E.g.f.: (9*exp(10*x) - 9 + 10*x)/10. (End)