%I #6 Oct 20 2014 17:15:17
%S 1,1,2,10,70,550,4730,44378,45646
%N Bidendriforms (see Foissy and Patras for precise definition).
%H Loïc Foissy and Frédéric Patras, <a href="http://arxiv.org/abs/1205.2986">Natural endomorphisms of shuffle algebras</a>, arXiv preprint arXiv:1205.2986, 2012
%K nonn
%O 1,3
%A _N. J. A. Sloane_, Oct 22 2012