131484domain: NAppears in sequencesSum{T(i,n-i): i=0,1,...,n}, array T as in A047120.at n=18A047121Number of paths from (0,0) to (n,n) using only steps North, Northeast and East (i.e., steps E(1,0), D(1,1), and N(0,1)) that do not cross y=x "vertically".at n=8A268208