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%I #8 Aug 08 2018 05:43:33
%S 1,0,1,3,5,12,22,50,95,210,406,882,1722,3696,7260,15444,30459,64350,
%T 127270,267410,529958,1108536,2200276,4585308,9111830,18929092,
%U 37650172,78004500,155266100,320932800,639191160
%N Number of permutations in S_n with a certain property.
%H Frank Schmidt and Rodica Simion, <a href="https://doi.org/10.1007/BF01834201">Card shuffling and a transformation on S_n</a>, Aequationes Math. 44 (1992), no. 1, 11-34.
%p binomial(n-2,floor(n/2)-1) + floor((n-1)/2)*binomial(n-3,floor(n/2)-2);
%K nonn,easy
%O 1,4
%A _N. J. A. Sloane_.
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