18458415299domain: NAppears in sequencesNumber of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, 0), (-1, 1, 0), (0, 1, 1), (1, -1, -1)}.at n=21A148310