143244

Appears in sequences

• Number of bipartite outerplanar graphs on n unlabeled nodes.at n=13A111759
• Number of permutations on [n] whose up-down signature has nonnegative partial sums and which have exactly two descents.at n=10A321268
• Number T(n,k) of permutations p of [n] with exactly k descents such that the up-down signature of p has nonnegative partial sums; triangle T(n,k), n>=0, 0<=k<=max(0,floor((n-1)/2)), read by rows.at n=33A321280