Need an HP employee to answer this question

[parisse]

isPrime does the Miller-Rabin test on the Prime.
powmod(a,n,m) is computed by the fast powering algorithm, it does not compute a^n before taking remainder.
nprimes is a Giac/Xcas command, but it is not available on the Prime (perhaps we could add it?). Note that ithprime might be useful to implement nprimes, as a first step using an asymptotic guess.