Rooted graph

From Wikipedia, the free encyclopedia

In mathematics, and, in particular, in graph theory, a rooted graph is a mathematical graph in which one node (graph theory) is labelled in a special way to distinguish it from the graph's other nodes. This special node is called the root of the graph.

The number of rooted graphs for 1, 2, ... nodes is 1, 2, 6, 20, 90, 544, ... (sequence A000666 in OEIS)