Function: removeprimes
Section: number_theoretical
C-Name: removeprimes
Prototype: DG
Help: removeprimes({x=[]}): remove primes in the vector x from the prime table.
x can also be a single integer. List the current extra primes if x is omitted.
Doc: removes the primes listed in $x$ from
the prime number table. In particular \kbd{removeprimes(addprimes())} empties
the extra prime table. $x$ can also be a single integer. List the current
extra primes if $x$ is omitted.