27159132domain: NAppears in sequencesa(n) = 21*(n+1)*binomial(n+6,9).at n=10A027821a(n) = 42*binomial(n,10).at n=22A088626Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of 2 n steps taken from {(-1, 0), (1, -1), (1, 1)}.at n=11A151379