How many regions can be selected in a 8 by 8 chess board?
Definition of region: A region is a set of cells that are all connected together(by edge). i.e. a possible region:
I want to run(or do complexity analysis for) a backtrack algorithm, and need to know the number of possible regions.
The value you are looking for is $51016818604894742$ and it is part of OEIS sequence A059525.