

A228113


First differences of A057793.


4



5, 21, 142, 1059, 8360, 68940, 586140, 5096885, 45085903, 404203228, 3663001812, 33489858047, 308457620524, 2858876200536, 26639628764285, 249393770865090, 2344318815695001, 22116397127183516, 209317713015989446, 1986761935255798075, 18906449883376272709
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OFFSET

1,1


COMMENTS

This sequence is an approximation to the number of primes with n digits (A006879). The error in the approximation is tabulated in A228114.
Because A057793(n)= Riemann(10^n) is not defined for n=0, we set its value to zero for our purpose of defining the differences.


REFERENCES

John H. Conway and R. K. Guy, "The Book of Numbers," Copernicus, an imprint of SpringerVerlag, NY, 1996, page 144146.


LINKS

Vladimir Pletser, Table of n, a(n) for n = 1..100
Eric Weisstein's World of Mathematics, Prime Counting Function.
Eric Weisstein's World of Mathematics, Riemann Prime Counting Function.


FORMULA

a(n)= A057793(n) A057793(n1).


EXAMPLE

For n =1, A057793(1) A057793(0)=50=5


CROSSREFS

Cf. A006879, A057793, A228111  A228116.
Sequence in context: A050910 A220378 A230645 * A306589 A221513 A284231
Adjacent sequences: A228110 A228111 A228112 * A228114 A228115 A228116


KEYWORD

nonn


AUTHOR

Vladimir Pletser, Aug 10 2013


STATUS

approved



