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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
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
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 March 19 01:34 EDT 2024. Contains 370952 sequences. (Running on oeis4.)