The score is the sum of all valid interactions.
Concept Overview:
A coefficient cell is a special board cell that acts as a multiplier. Its numeric value is denoted by ki and scales the contribution of all adjacent number cells.
In the board layout, this corresponds to the coefficient cell (e.g. A2).
A number cell contains a numeric value xj. These values do not multiply directly; instead, they are first summed if they are adjacent to a coefficient cell.
Only number cells that are adjacent to a coefficient cell contribute to its score.
Adj(i) is the set of all cells that share a common edge with cell i. Diagonal neighbors are not included.
The center cell is i; highlighted cells belong to Adj(i).