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

1,4

Links

Table of n, a(n) for n=1..27.

Mathematica

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

Prog

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

Crossrefs

Cf. A003604.

Sequence in context: A318798 A318851 A052328 * A036717 A000080 A327017

Adjacent sequences: A133225 A133226 A133227 * A133229 A133230 A133231

Keyword

nonn

Author

Giovanni Teofilatto, Oct 13 2007

Extensions

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

Status

approved