Andreas Ernst wrote:

> Some people noted, that the url I gave was not

> valid. Please try to access the ps file on a sieve

> for twin primes via my homepage

>

> http://www.rzuser.uni-heidelberg.de/~aernst

>

> You find the ps file in the section 'Hobbies'.

I'm sorry but your methods are well-known.

All primes above 3 are on the form 6n+/-1. You use this with a wheel of size 6

to avoid numbers divisible by 2 or 3. That is common. Larger wheels, e.g. of

size 5# = 30 to also avoid numbers divisible by 5, are more efficient in many

cases.

Your second idea is to represent the potential twin 6n+/-1 with a single bit

representing n instead of 2 bits, one for each of the 2 numbers. This is also a

very common technique when searching a set of 2 or more simultaneous primes. If

a set of m primes is required, m=2 for twin primes, then each sieve prime p runs

through m loops to strike out n for which the i'th number (1<=i<=m) in the m-set

is divisible by p.

--

Jens Kruse Andersen