tables of p(n) and/or pi(n)
Hans Havermann
pxp at rogers.com
Mon Sep 19 20:16:49 CEST 2005
Joshua Zucker wrote:
> The easy compression fits 30 numbers per byte, by using one bit for
> prime/not prime for each of the number equal to 1, 7, 11, 13, 17, 19,
> 23, 29 mod 30.
>
> So it's not 30 primes per byte, but rather 30 numbers.
>
> With that scheme, since pi(3*10^13) is roughly 10^12, it would take
> only (3*10^13)/30 bytes to store the primality of all of them, so
> indeed, 1TB is about right (not 10TB as in your corrected post).
To be fair, I'm not just storing primality, but also relatively fast
recovery of pi(prime) values.
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