20226421380domain: NAppears in sequencesNumber of Dumont permutations of the first kind of length 2n avoiding the patterns 1423 and 4132.at n=17A125187Number of lattice paths from (0,0) to (n,0) that do not go below the x-axis and consist of steps U=(1,1), D=(1,-1) and H=(1,0), where H-steps are only allowed if y=1.at n=34A224747