Re: primepi([from,until])

[Charles Greathouse <crgreathouse@gmail.com>]

Is

https://github.com/kimwalisch/primecount

license-compatible? Because it’s really fast (AFAIK, the fastest code out there).

On Thu, Feb 1, 2024 at 3:14 PM Bill Allombert <Bill.Allombert@math.u-bordeaux.fr> wrote:

On Thu, Feb 01, 2024 at 09:08:00PM +0100, Ruud H.G. van Tol wrote:
>
> I'm adding
>
> a(n) = #primes([n^2/4, (n+1)^2/4]);
>
> to https://oeis.org/A220492
>
> and was wondering if primepi() should grow a primepi([x1, x2])variant,
> to return the number of primes p, x1 <= p <= x2.

just do primepi(floor(x2))- primepi(ceil(x1)-1) or something ?

PS: I have vague plans to rewrite primepi to be faster....

Cheers,
Bill