This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A379608 #12 Jun 28 2025 22:14:13 %S A379608 1,2,5,11,33,74,144,232,639 %N A379608 Number of unlabeled Riordan posets with n elements. %C A379608 Posets associated to binary Riordan matrices are called Riordan posets. %H A379608 G. S. Cheon et al., <a href="https://doi.org/10.1016/j.laa.2021.10.002">Riordan posets and associated incidence matrices</a>, Linear Algebra and its Applications, 632 (2022), 308-331. %e A379608 For example, all the posets up to 3 elements are Riordan posets. %Y A379608 Cf. A000112, A000608, A349401 %K A379608 nonn,more %O A379608 1,2 %A A379608 _Salah Uddin Mohammad_, Dec 27 2024 %E A379608 a(9) from _Salah Uddin Mohammad_, Jun 28 2025