What is a formula?

Research Horizons Seminar
Wednesday, September 26, 2018 - 12:20pm
1 hour (actually 50 minutes)
Skiles 005
University of California, Los Angeles
Integer sequences arise in a large variety of combinatorial problems as a way to count combinatorial objects.  Some of them have nice formulas, some have elegant recurrences, and some have nothing interesting about them at all.  Can we characterize when?  Can we even formalize what is a "formula"?  I will try to answer these questions by presenting many examples, results and open problems. Note:  This is an introductory general audience talk unrelated to the colloquium.