(31,1,8) = {31:1:143:15:128:160}
(-2,1,8) = {-2:1:143:16:127:161}
(-f,1)'s a is one less than (e,1)'s a, and (-f,1)'s b is one greater than (e,1)'s b, but only for this particular t value. At other t values, they're further apart. For example:
(31,1,2) = {31:1:23:3:20:28}
(-2,1,2) = {-2:1:11:4:7:17}
and
(31,1,12) = {31:1:303:23:280:328}
(-2,1,12) = {-2:1:311:24:287:337}
So at this particular t value, (e,1) and (-f,1)'s a and b values are one unit apart. Just blindly looking for unverified patterns here, but the difference is |f|. If these rules apply to all other values (or at least the first one), this t value would seem to act like a mirror point or the turning point of a parabola with a predictable gap where the gap between these a and b values from (e,1) and (-f,1) gets larger either side of this t value (and probably harder to predict). I've spent about 5 minutes on this so I don't know how that applies to factorizing c, but other than that, both infinite sets do that thing with the a and b values swapping (i.e. a[t] = b[t-1], I don't know about b). If nobody else does I might have a look at these other latest VQC clues at some point tonight.
All of that said and done, yet again, I feel like I'm completely out of the loop: VA, how did you get a t value of 8 with the na transform?