A093852 a(n) = 10^(n-1) - 1 + n*floor(9*10^(n-1)/(n+1)).

4, 69, 774, 8199, 84999, 871425, 8874999, 89999999, 909999999, 9181818179, 92499999999, 930769230759, 9357142857140, 93999999999999, 943749999999999, 9470588235294111, 94999999999999999, 952631578947368403, 9549999999999999999, 95714285714285714279

Offset: 1

Author

Amarnath Murthy, Apr 18 2004

Keywords

• easy
• nonn

Comments

This sequence is the main diagonal of A093850.

Examples

			n-th row of the following triangle contains n uniformly located n-digit numbers. i.e. n terms of an arithmetic progression with 10^(n-1)-1 as the term preceding the first term and (n+1)-th term is the largest possible n-digit term.
Given the triangle defined in A093850:
...4;
..39   69;
.324  549  774;
2799 4599 6399 8199.....
then this sequence is the leading diagonal.
		

Links

• G. C. Greubel, Table of n, a(n) for n = 1..995

Crossrefs

Cf. A093846, A093847, A061772, A093450, A072875.

Programs

Magma

[10^(n-1) -1 +n*Floor(9*10^(n-1)/(n+1)): n in [1..25]]; // G. C. Greubel, Mar 21 2019

Maple

A093852 := proc(n)
        r := n ;
        10^(n-1)-1+r*floor(9*10^(n-1)/(n+1)) ;
end proc:
seq(A093852(n),n=1..50) ; # R. J. Mathar, Oct 01 2011

Mathematica

Table[10^(n-1) -1 +n*Floor[9*10^(n-1)/(n+1)], {n,25}] (* G. C. Greubel, Mar 21 2019 *)

PARI

{a(n) = 10^(n-1) -1 +n*floor(9*10^(n-1)/(n+1))}; \\ G. C. Greubel, Mar 21 2019

Sage

[10^(n-1) -1 +n*floor(9*10^(n-1)/(n+1)) for n in (1..25)] # G. C. Greubel, Mar 21 2019