I have an Erdős number of 3. This co-authorship graph shows some connections between mathematicians and HCI researchers:

          +-----------------------------------------------+--- Paul Erdos --------+
          |                                               |                       |
 David Michael Avis                        +-------- Maria M. Klawe -------+   Charles J. Colbourn
          |                                |              |                |      |             |
  Jean-Marc Robert         Michael Chi Hung Wu   Joanna Lynn McGrenere -- Kellogg S. Booth     Derek G. Corneil
          |                        |         |                 |               |                 |
 Michael J. McGuffin -- Ravin Balakrishnan   +------------ Ronald M. Baecker --+               Igor Jurisica
          |                              |                     |                                 |
          |                             William A. S. Buxton --+                                 |
          |                                                                                      |
          +--------------------------------------------------------------------------------------+