51147domain: NAppears in sequencesTriangle read by rows: T(n,k) (0 <= k <= floor(n/2)) is the number of lattice paths from (0,0) to (2n,0) consisting of steps U=(1,1), D=(1,-1), H=(2,0), never going below the x-axis (i.e., Schroeder paths) and having k UH's.at n=27A110220