4172198

Appears in sequences

• Number of connected graphs on n labeled nodes, each node being colored with one of 2 colors, such that no edge joins nodes of the same color.at n=8A002027
• Number of labeled connected digraphs on n nodes where every node has indegree 0 or outdegree 0 and no isolated nodes.at n=6A002031
• Triangular array read by rows. T(n,k) is the number of 2-colored labeled graphs on n nodes with exactly k connected components; n>=1, 1<=k<=n.at n=28A228892
• Array read by antidiagonals: T(n,k) is the number of connected graphs on n labeled nodes, each node being colored with one of k colors, where no edge connects two nodes of the same color.at n=63A322279
• T(n,k) is the number of connected labeled posets with n elements and rank k: triangle read by rows.at n=29A342501