# Difference between revisions of "Primorial"

## Definition

Let  be a natural number. The  primorial, sometimes denoted , is defined as the product of the first  prime numbers.

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An alternate definition of primorial, called here the primorial of the second kind, is defined as the product of all the primes less than or equal to a given number. Note that the logarithm of the primorial of the second kind is the first Chebyshev function.

## Behavior

The ID of the sequence in the Online Encyclopedia of Integer Sequences is A002110

### Initial values

The values of primorials at  are respectively .