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# Seventeen or Bust/Factoring

Factoring is the most difficult part, easier are sieving and PRP as instructions are very rare to find. But hey, this article was made to give instructions, right? Factoring for Seventeen or Bust is made by the P-1 factoring method only.

The programs commonly used to P-1 factor these numbers are Prime95 and SBFactor v1.2. Be warned that SBFactor doesn't allow resuming a factoring in the middle of it, but the pick is yours. You'll also need an updated sob.dat and an updated (it's recommended to update these weekly)results.txt

For factoring with Prime95, you'll also want a copy of the great utility make_worktodo.

## Reserving a range

Go to the P-1 official thread and post to reserve a range available below the green line. Post like that:

```nmin nmax username ? [reserved]
```

NOTE: Make sure you can keep up with PRP (factor before the PRP tests have been started). A good rule of thumb is to check here and add 100K to the n value. This should give you a two week headstart.

## Working on the range

Put the sob.dat and results.txt on the same directory as your chosen factoring program.

### Instructions for Prime95

Rename the make_worktodo.bat to make_worktodo.txt. Input the starting point for your range in set nmin, the ending in set nmax. The sievedepth is around 49 and 50, the factorworth is best between 1.5 and 2, around 1.7. Save it and rename it to make_worktodo.bat. Run it. Then start Prime95 and click on "Just Stress Testing". Wait until it's done.

### Instructions for SBFactor

Run the program in the command line adding the options:

```sbfactor <starting point> <ending point> 49.5 1.7 (optional: <cpu to run on> <total cpus>) <memory available in MB>"
```

If you really need to resume it, wait for a P-1 factoring to finish, and use that as the starting point next time you start it.

## Reporting results

Post a message in the P-1 official thread telling you completed the range, in the form:

```nmin nmax username <number of factors>	[complete]
```

And then submit the factors here in the form:

```factor | k*2^n+1
```

NOTE:Some factors might be big enough not to be recieved by this page; then try here.