Some other hints about generating optimized exploratory sequences:
Conjugate gradients algorith. Can be generalized in several ways
Space filling curves on grids can be constructed at different scales of detail – give a way to map large integers into grid locations, where near values tend to be near & far values tend to be far – can be used to hash the set of neighborhoods already visited or waiting for a go at next level expansion. Being in a grid site at level I can be used as a basis for rejection sampling filter in the low discrepancy seque
One can look ahead at the next N values of any given discrepancy sequence & sort it in some way – e.g. distance from current point or from highest level of space filling curve or grid where a hit is matched. Again, this can be done with rejection sampling, and it can be used as another virtual dimension for generalized conjugate gradients (go to a less explored area or keep optimizing here?)