A228065 Difference of consecutive integers nearest to (10^n)/log(10^n) (A057834).

4, 18, 123, 941, 7600, 63696, 548039, 4808260, 42826261, 386039540, 3513837172, 32243075171, 297881471562, 2768030763779, 25850862018051, 242481085729315, 2283239371770773, 21572797793887019, 204448571890127322, 1942896366409284492

Offset

1,1

Comments

This sequence gives an approximation of the number of primes with n digits (A006879); see A228066.

Note that A057834(n) = (10^n)/log(10^n) is not defined for n=0. Its value is set arbitrarily to 0.

Links

Vladimir Pletser, Table of n, a(n) for n = 1..500

Eric Weisstein's World of Mathematics, Prime Counting Function.

Formula

a(n) = A057834(n) - A057834(n-1).

Example

For n = 1, A057834(1) - A057834(0) = 4-0 = 4.

Crossrefs

Cf. A006879, A057834, A228066.

Sequence in context: A112294 A346680 A292500 * A317377 A332748 A215691

Adjacent sequences: A228062 A228063 A228064 * A228066 A228067 A228068

Keyword

nonn

Author

Vladimir Pletser, Aug 06 2013

Status

approved