When to stop sieving and start using LLR, PRP or PFGW is difficult to establish. There are many things to take into account:
* it is nice to have some nonsieve testing happening on smaller 'n'
* the time take to test '2*n' is just over four times of that for 'n'
* sieving is proportional to the square root of the range
* judging NewPGen  elimination timing goes up and down
* LLR/PRP/PFGW timings vary but not exactly proportional to size
* different computer architectures
* demand
Originally, I was going to sieve in 100,000 'n' blocks. I have decided that the work involved to complete 'n' to 1 million is enough work to organise for now.
Of course Paul Jobling's NewPGen is to be attributed when submitting primes to the top 5000 primes. Phil Carmody helped Paul with some maths to get a fixedk sieve running faster.
After my last message NewPGen dropped to 3:20 minutes, but now reads 5:48 minutes. So by rough calculations the block 300,000400,000 can be released for testing soon. There are two blocks left from 200,000300,000 free for testing ( email me ). How I break up 300,000400,000 depends on feedback from participants, but 2 GHz weeks seems about the right size for a block.
