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Mathematica Teacher's Edition

Built-in Functions

Mathematical Functions

Number Theory

PrimePi

PrimePi[x] gives the number of primes less than or equal to x.

The argument of PrimePi can be any positive real number.
PrimePi[1] gives 0.
See The Mathematica Book on the web: Section 3.2.4.
Implementation Notes: see Section A.9.4.
See also: Prime, Zeta.

Further Examples