A092871 Number of composites < 10^n.

0, 4, 73, 830, 8769, 90406, 921500, 9335419, 94238543, 949152464, 9544947487, 95881945185, 962392087980, 9653934463159, 96795058249196, 970155429577329, 9720761658966073, 97376442842345765, 975260045712259138, 9765942332723655391, 97779180397439081158

Offset: 0

Author

Enoch Haga, Mar 08 2004

Keywords

• nonn

Comments

The number 1 is omitted from the count as it is neither prime nor composite

Examples

			10^3 = 1000. 1000-2 = 998. a(3) = 830 because the 830 composites+168 primes must total 998.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 0..29 (calculated using the b-file at A006880)
• Chris Caldwell, The Prime Pages, How many primes are there? Table 1. Values of pi(x).

Crossrefs

Cf. A065894, A006880, A092801, A092802.

Programs

Mathematica

Table[10^i-PrimePi[10^i]-2,{i,14}] (* Harvey P. Dale, Oct 01 2011 *) (* Mathematica's implementation of PrimePi does not work for 10^15 or above *)

Formula

For n>0, a(n) = A065894(n) - 1 = 10^n - 2 - A006880(n). - Max Alekseyev, Aug 15 2013

Extensions

Edited by Max Alekseyev, Aug 15 2013