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”).
%I #2 Mar 31 2012 10:29:58
%S 1,2,5,16,62,280,1440,8296,52864,368848,2794864,22842048,200201408,
%T 1872466944,18608903968,195778297664,2173272774016,25380361760000,
%U 311011886153856,3989579297299712,53458990592638976,746817531317769728
%N Number of permutations of length n that can be sorted in 2^(n-1)-1 steps of Elizalde and Winkler's homing algorithm
%C The maximum number of steps that the homing algorithm can take to sort a permutation of length n is 2^(n-1)-1. This sequence counts permutations for which it is possible to use these many steps.
%D S. Elizalde and P. Winkler, Sorting by Placement and Shift, Proceedings of the Twentieth Annual ACM-SIAM Symposium on Discrete Algorithms, SODA 2009.
%H S. Elizalde and P. Winkler, <a href="http://arxiv.org/abs/0809.2957"> Sorting by placement and shift</a>
%F a(n) is the coefficient of t^n in the generating function F(t,t), where F(u,v) satisfies the partial differential equation F(u,v)=u*v+u*v*D_u(f)+u*v*D_v(f)-u^2*v^2*D_u(D_v(f)).
%K nonn
%O 2,2
%A _Sergi Elizalde_, Feb 18 2010