'Check out his idea here:
I can't see how polytope has proved that all ab+1 are composites.
Indeed using this code:
for (i=1,n/2,for (j=i+1,n/2,
yields the following exceptions.
(note 16:4,7 implies that (16!/2+4) * (16!/2+7) + 1 =
109440784174463838480384029 is prime)
We did adopt a policy of at least one prime in the thread, as the
all-composite sets seemed to be too easy; although we did not manage a proof
of the existence of arbitary sets as attempted by polytope.
The sets mentions are not the first composite-only runs:
sums up to current knowledge of the problem.