A Graph which is connected (as a Topological Space), i.e., there is a path from any point to any other point in the Graph. The number of -Vertex (unlabeled) connected graphs for , 2, ... are 1, 1, 2, 6, 21, 112, 853, 11117, ... (Sloane's A001349).

**References**

Chartrand, G. ``Connected Graphs.'' §2.3 in *Introductory Graph Theory.* New York: Dover, pp. 41-45, 1985.

Sloane, N. J. A. Sequence
A001349/M1657
in ``An On-Line Version of the Encyclopedia of Integer Sequences.''
http://www.research.att.com/~njas/sequences/eisonline.html and Sloane, N. J. A. and Plouffe, S.
*The Encyclopedia of Integer Sequences.* San Diego: Academic Press, 1995.

© 1996-9

1999-05-26