Journal of Integer Sequences, Vol. 15 (2012), Article 12.4.4 |
Abstract:
Received January 12 2011; revised versions received June 5 2011; October 26 2011; December 11 2011; March 23 2012. Published in Journal of Integer Sequences, April 9 2012. Withdrawn because of errors, April 18 2012. Revised versions received April 25 2012; August 3 2012. Published in Journal of Integer Sequences, September 3 2012.