A379608 Number of unlabeled Riordan posets with n elements.

1, 2, 5, 11, 33, 74, 144, 232, 639, 1406, 3164, 4992, 12501, 26973, 55937

Offset

1,2

Comments

Posets associated to binary Riordan matrices are called Riordan posets.

Links

Table of n, a(n) for n=1..15.

G. S. Cheon et al., Riordan posets and associated incidence matrices, Linear Algebra and its Applications, 632 (2022), 308-331.

Example

For example, all the posets up to 3 elements are Riordan posets.

Crossrefs

Cf. A000112, A000608, A349401

Sequence in context: A056364 A205799 A296549 * A056365 A276548 A353016

Adjacent sequences: A379605 A379606 A379607 * A379609 A379610 A379611

Keyword

nonn,more

Author

Salah Uddin Mohammad, Dec 27 2024

Extensions

a(9) from Salah Uddin Mohammad, Jun 28 2025

a(10)-a(15) from Md. Abu Bakkar, Jan 08 2026

Status

approved