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

          +---------------------+-----------------------------------------------+--- Paul Erdos --------+
          |                     |                                               |                       |
  Michael Klugerman    David Michael Avis                        +-------- Maria M. Klawe -------+   Charles J. Colbourn
          |                     |                                |              |                |      |             |
Jeremy R. Cooperstock   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 --+                                 |
                                |                                                                                      |
                                +--------------------------------------------------------------------------------------+