i'm gonna skip through explaining what this is and get right to what i'm up to.

basically, i hacked up the GIMPS P-1 factoring code and made it do proth numbers. well, maybe.

the thing is, I haven't been able to do much serious testing of it because i have no way to know what it should find for which values.

it has found factors on some numbers but all of them are rather trivial factors (ie 5, 7, 11).

if you know how to test this, download it and report back when you get some results. i'd be very impressed if you found a factor for a currently unfactored number around n=4M.

program syntax is:

ecm.exe <k> <n-start> <n-quit> <B1> <B2>

so if you wanted to check 4847*2^4000000+1, you'd do

ecm.exe 4847 4000000 4000001 1000000 40000000

if you make n-quit larger by more than 1, it will step though multiple "n" as a quick way to batch things for testing.

you'll probably have to know a bit about P-1 factoring to test this correctly. if you feel you know a lot and have visual studio installed, email me and i'll send you the code for you to look though. it's a derivative of what's contained in emc.c in the GIMPS source located at http://www.mersenne.org/gimps/source23.zip

so let me know if you think this works.

http://www-personal.engin.umich.edu/...20factorer.zip