Triangle read by rows: T(n, k) is the number of walks of length n on the Z X Z grid with unit steps in all four directions (NSWE) starting at (0, 0), and ending on the vertical line x = 0 if k = 0, or on the line x = k or x = -(n + 1 - k) if k > 0.

A379822

Triangle read by rows: T(n, k) is the number of walks of length n on the Z X Z grid with unit steps in all four directions (NSWE) starting at (0, 0), and ending on the vertical line x = 0 if k = 0, or on the line x = k or x = -(n + 1 - k) if k > 0.