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.

A002027

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.

Terms

    a(0) =1a(1) =2a(2) =2a(3) =6a(4) =38a(5) =390a(6) =6062a(7) =134526a(8) =4172198a(9) =178449270a(10) =10508108222a(11) =853219059726

External references