%I #10 Dec 03 2016 08:48:05
%S 1,1,4,40,778,25306
%N a(n) = A278589(n)/2^n.
%H Z. Hamaker, E. Marberg, B. Pawlowski, <a href="https://arxiv.org/abs/1601.02269">Involution words II: braid relations and atomic structures</a>, arXiv preprint arXiv:1601.02269, 2016. See Remark following Th. 6.18.
%Y Cf. A212417, A278589.
%K nonn,more
%O 0,3
%A _N. J. A. Sloane_, Dec 02 2016