515302domain: NAppears in sequencesa(n) = A026907(2*n, n-1).at n=7A026910Number 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, 0, 1), (0, -1, 0), (0, 1, -1), (1, 1, 0)}.at n=11A149326