1,2

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

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

C. K. Caldwell, How Many Primes Are There?

(Haskell)

a053621 = round . (\x -> x / (log x - 1)) . fromIntegral

-- Reinhard Zumkeller, Apr 30 2014

Cf. A000720, A047784, A050499.

Sequence in context: A300528 A157422 A061644 * A210107 A266604 A018831

Adjacent sequences: A053618 A053619 A053620 * A053622 A053623 A053624

sign

Henry Bottomley, Mar 21 2000

approved