A133228 Number of primes < square root of n!.

0, 0, 1, 2, 4, 9, 19, 46, 110, 291, 822, 2455, 7740, 25635, 88849, 320749, 1202674, 4670156, 18741145, 77553119, 330321299, 1445829174, 6493985903, 29891948760, 140843699641, 678576973614, 3339785593878

Offset: 1

Author

Giovanni Teofilatto, Oct 13 2007

Keywords

• nonn

Crossrefs

Cf. A003604.

Programs

Mathematica

Table[PrimePi[Sqrt[n! ]], {n, 27}] (* Robert G. Wilson v *)

PARI

a(n)=primepi(sqrtint(n!)) \\ Charles R Greathouse IV, Sep 15 2015

Extensions

More terms from Stefan Steinerberger and Robert G. Wilson v, Oct 14 2007