116538domain: 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=10A149433a(0) = 0, a(1) = 1; for n > 1, a(n) = Sum_{k=0..n-2} a(k) XOR a(n-k-2).at n=20A318619