OFFSET
1,2
REFERENCES
John H. Conway and R. K. Guy, "The Book of Numbers," Copernicus, an imprint of Springer-Verlag, NY, 1995, Page 146.
LINKS
Eduard Roure Perdices, Table of n, a(n) for n = 1..28
Wikipedia, Prime number theorem
FORMULA
a(n) ~ 10^n/(n log 10)^2. - Charles R Greathouse IV, Mar 22 2015
MATHEMATICA
Table[ PrimePi[10^n] - Round[ N[ 10^n/Log[ 10^n ] ] ], {n, 1, 13} ]
PROG
(PARI) a(n)=primepi(10^n)-round(10^n/log(10^n)) \\ Charles R Greathouse IV, Mar 22 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Nov 08 2000
EXTENSIONS
More terms from Jud McCranie, Jun 21 2005
Corrected and extended by Henry Bottomley, Aug 10 2005
a(22) to a(25) from Vladimir Pletser, Aug 10 2013
STATUS
approved