4747010

Appears in sequences

• Number of labeled digraphs where every node has indegree 0 or outdegree 0 and no isolated nodes.at n=8A052332
• Triangle T(n,k) of strongly graded (3+1)-free partially ordered sets (posets) on n labeled vertices with height k.at n=29A222864
• Triangle read by rows: T(n,k) is the number of labeled tiered posets with n elements and height k.at n=38A361956