%I #12 Jan 05 2016 11:29:36
%S 0,2,11,49,223,1065,5337,28231,158939
%N Length of longest chain of nonempty proper inverse subsemigroups of the dual symmetric inverse monoid.
%H P. J. Cameron, M. Gadouleau, J. D. Mitchell, Y. Peresse, <a href="http://arxiv.org/abs/1501.06394">Chains of subsemigroups</a>, arXiv preprint arXiv:1501.06394 [math.GR], 2015.
%K nonn,more
%O 1,2
%A _N. J. A. Sloane_, Sep 21 2015