1553630domain: NAppears in sequencesa(n) = f(n,n) where f is given in A034261.at n=10A034267Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, 1), (0, -1), (1, 0)}.at n=19A151497