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A133228 Number of primes < square root of n!. 10
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 (list; graph; refs; listen; history; text; internal format)
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: A036718 A134964 A052328 * A036717 A000080 A153447

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

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Last modified July 21 02:57 EDT 2017. Contains 289629 sequences.