OFFSET
1,2
COMMENTS
n/(log(n)-1) is a better approximation than n/log(n) to pi(n) the number of primes <= n, though worse than the logarithmic integral or the Riemann prime number formula.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
C. K. Caldwell, How Many Primes Are There?
Pierre Dusart, Estimates of Some Functions Over Primes without R.H., arXiv:1002.0442 [math.NT], 2010.
MATHEMATICA
Table[Round[n/(Log[n]-1)], {n, 1, 80}] (* G. C. Greubel, May 17 2019 *)
PROG
(Haskell)
a053621 = round . (\x -> x / (log x - 1)) . fromIntegral
-- Reinhard Zumkeller, Apr 30 2014
(PARI) vector(80, n, round(n/(log(n)-1))) \\ G. C. Greubel, May 17 2019
(Magma) [Round(n/(Log(n)-1)): n in [1..80]]; // G. C. Greubel, May 17 2019
(Sage) [round(n/(log(n)-1)) for n in (1..80)] # G. C. Greubel, May 17 2019
CROSSREFS
KEYWORD
sign
AUTHOR
Henry Bottomley, Mar 21 2000
STATUS
approved