September 10, 2019
12:00PM ET
![Group Photo](https://olsume.org/wp-content/uploads/2020/12/2019-09-10.jpg)
April 28, 2020
12:00PM ET
![Rachel Levy](https://olsume.org/wp-content/uploads/2020/12/2020-04-28.jpg)
- Rachel Levy (North Carolina State University)
January 24, 2023
12:00PM ET
![Image of Tim Chartier](https://olsume.org/wp-content/uploads/2023/01/chartier-scaled.jpg)
- Tim Chartier (Davidson College & The Museum of Mathematics)
September 12, 2023
12:00PM ET
![Photo of Judy Holdener](https://olsume.org/wp-content/uploads/2023/08/holdener-scaled.jpg)
- Judy Holdener (Kenyon College)
November 21, 2023
12:00PM ET
![Paul Hand](https://olsume.org/wp-content/uploads/2023/11/hand.jpg)
- Paul Hand (Northeastern University )