30606domain: 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, 0, 0), (1, -1, 0), (1, 1, -1), (1, 1, 1)}.at n=9A149433G.f. satisfies A(x) = 1 / (1 - x^4*A(x)^4 / (1 - x)).at n=21A376491