[R.D. Silverman]

I just found an interesting bug in my siever. I discovered it while
making some improvements, including a larger sieve region.

Here is one instance. For special_q = 256300217 with root 137499035,
my lattice reduction routine returned (36738082, 6593) (137499035, 1)

This is not correct. The problem, of course is integer overflow. The
routine uses signed ints.

Of course, since the reduced lattice is wrong, everything that follows is
wrong and no relations get produced.

I had been getting a very low relation yield rate for the larger special q's
on my current factorization. This explains it. I've been losing valid
relations.

I am going to have to change the latred routine to use 64 bit ints.