A067116 Floor(decimal concatenation of first n natural numbers/their sum).

1, 4, 20, 123, 823, 5878, 44091, 342935, 2743484, 224466889, 18705574106, 1582779347450, 135666801210013, 11757789438201155, 1028806575842601095, 90777050809641273099, 8069071183079224275500, 721969526907088487807963

Offset: 1

Author

Amarnath Murthy, Jan 08 2002

Keywords

• easy
• nonn
• base

Examples

			a(6) = floor (123456 / 21) = 5878.
		

Links

• Harry J. Smith, Table of n, a(n) for n = 1..100

Programs

Mathematica

Table[Floor[FromDigits[Flatten[IntegerDigits/@Range[n]]]/Total[Range[n]]],{n,20}] (* Harvey P. Dale, Jul 22 2022 *)

PARI

digitsIn(x)= { local(d); if (x==0, return(1)); d=1 + log(x)\log(10); if (10^d == x, d++, if (10^(d-1) > x, d--)); return(d) } Concat(a, b)= { return(a*10^digitsIn(b) + b) } { c=0; s=0; for (n=1, 100, c=Concat(c, n); s+=n; write("b067116.txt", n, " ", floor(c/s)) ) } \\ Harry J. Smith, May 24 2010

Extensions

More terms from several contributors

Edited by Charles R Greathouse IV, Apr 26 2010