A076960 a(n) is the number of primes between n! and (2n)!.

0, 8, 125, 4222, 258659, 25306159, 3610490130, 706003793908, 181035032176791, 58893601709293849, 23688535118130027712, 11539922212278290441881

Offset

1,2

Links

Table of n, a(n) for n=1..12.

Formula

a(n) = A003604(2*n) - A003604(n), for n >= 2. - Amiram Eldar, Jun 11 2024

Example

a(2) = 8 as pi(24) = 9 and pi(2) = 1.

Maple

with(numtheory): 0, seq(pi((2*n)!)-pi(n!), n=2..5); # Emeric Deutsch, Jul 31 2005

Mathematica

a[n_] := PrimePi[(2n)! - 1] - PrimePi[n! ]; Table[a[n], {n, 1, 8}] (* Ryan Propper, Sep 11 2005 *)

Crossrefs

Cf. A003604, A076959.

Sequence in context: A215793 A273279 A227851 * A298623 A035130 A055762

Adjacent sequences: A076957 A076958 A076959 * A076961 A076962 A076963

Keyword

nonn,more

Author

Amarnath Murthy, Oct 21 2002

Extensions

Corrected and extended by Emeric Deutsch, Jul 31 2005

a(7)-a(8) from Ryan Propper, Sep 11 2005

a(9) from Donovan Johnson, Mar 10 2010

a(10)-a(12) from Amiram Eldar, Jun 11 2024

Status

approved