I guess I would like to know from someone who thought such things were indications of the workings of a deity what sorts of patterns would count to them as not being indications of a deity. I'm inclined to think that some sort of order is a simple requirement of there being a universe at all, and so it seems that some indications of such order--whether highly complex or simple--would inevitably be evident in that universe. As a result, it is difficult for me to see why some particular patterns would indicate anything religiously significant--after all, it is not as if the patterns themselves are divine signatures or fingerprints or the divine equivalent of DNA evidence. That one can have a religious response to such things, as Richard Heck proposes, I don't doubt; but that such a response is somehow rationally supportable, I do doubt.
Two answers come to mind:
(1) If we grant that mathematics is known with certainty, I think the same can be made for the laws of logic--for example, if P, then P... or either P or not-P.
(2) I can think of some reasons for supposing that even mathematical truths and the laws of logic aren't known with certainty. For one thing, axiomatized systems of reasoning (such as the logic and mathematics) are able to undergo modification, as a result of new discoveries--for example, the Euclidean axiom that the shortest distance between two points is a straight line is not an axiom in Eisteinian geometry (since gravity wells curve space). For another thing, I don't think we can automatically infer, from the fact that we find it impossible to imagine the falsity of something, that our beliefs about that subject must be true. Why couldn't we be so bad off that we are incapable of imagining what's true, and capable only of imagining some falsehood as truth?
Descartes takes this issue up in his Meditations on First Philosophy (especially in the First and Second Meditations). See what you think of his thoughts on this issue.