login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Number of linear extensions of a poset whose Hasse diagram consists of n binary shrubs with type E_n joins.
4

%I #13 Oct 31 2017 21:13:21

%S 1,3,99,11259,3052323,1620265923,1488257158851,2172534146099019,

%T 4736552519729393091,14708695606607601165843,

%U 62671742039942099631403299,355493170380387030721038571419,2618304731622723256262677112102883,24521387779014982719407393681918617443

%N Number of linear extensions of a poset whose Hasse diagram consists of n binary shrubs with type E_n joins.

%H Lars Blomberg, <a href="/A293952/b293952.txt">Table of n, a(n) for n = 0..100</a>

%H Jeffrey Remmel, S. Zheng, <a href="https://arxiv.org/abs/1611.09018">Rises in forests of binary shrubs</a>, arXiv preprint arXiv:1611.09018 [math.CO], 2016-2017.

%Y Cf. A293950, A293951, A293953.

%K nonn

%O 0,2

%A _N. J. A. Sloane_, Oct 29 2017

%E Terms a(11) and beyond from _Lars Blomberg_, Oct 31 2017