This installment of “Delving Deeper” contains two short articles that take different slants on themes that have run through many of the articles we have published: counting problems, Pascal's triangle, geometric series, and recurrence relations. It seems there is no end to the number of ways people can think about these topics.
Edited by Al Cuoco, email@example.com Center for Mathematics Education, Newton, MA 02458
Yukio Kobayashi, firstname.lastname@example.org, obtained his BE degree in 1983 from Waseda University, and his master's (1985) and PhD (1988) degrees from the University of Tokyo. He was a Frontier Research Program researcher at the Institute of Physical and Chemical Research (RIKEN) from 1989 to 1992. He has been an associate professor at Soka University, Tokyo.
James Metz, email@example.com, is an assistant professor of mathematics at Kapi'olani Community College, Honolulu, HI 96816. He is a volunteer for Teachers without Borders South Africa.