A338867 - OEIS

%I #9 Nov 29 2020 12:51:34

%S 1,1,5,38,424,6284

%N Related to the number of Hopf subalgebras of heap-preordered forests of vertex degree n.

%C It would be nice to have a more precise definition.

%H A. Mansuy, <a href="https://doi.org/10.1016/j.jalgebra.2014.04.017">Preordered forests, packed words and contraction algebras</a>, J. Algebra 411 (2014) 259-311, Section 3.1.

%K nonn,more

%O 0,3

%A _R. J. Mathar_, Nov 13 2020