A379608 Number of unlabeled Riordan posets with n elements.
1, 2, 5, 11, 33, 74, 144, 232, 639
Offset: 1
Examples
For example, all the posets up to 3 elements are Riordan posets.
Links
- G. S. Cheon et al., Riordan posets and associated incidence matrices, Linear Algebra and its Applications, 632 (2022), 308-331.
Extensions
a(9) from Salah Uddin Mohammad, Jun 28 2025
Comments