Number of labeled connected digraphs on n nodes where every node has indegree 0 or outdegree 0 and no isolated nodes.
A002031
Number of labeled connected digraphs on n nodes where every node has indegree 0 or outdegree 0 and no isolated nodes.
Terms
- a(0) =2a(1) =6a(2) =38a(3) =390a(4) =6062a(5) =134526a(6) =4172198a(7) =178449270a(8) =10508108222a(9) =853219059726
External references
- oeis: A002031