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%I #6 Mar 31 2012 10:30:53
%S 1,2,4,6,20,26,124,146,956,1050,9100
%N Number of signed permutations of length n invariant under the reverse complement and avoiding (-2, 1) and (2, -1).
%e For n = 2, the permutations are (1, 2), (2, 1), (-1, -2), and (-2, -1).
%K nonn
%O 0,2
%A _Andy Hardt_, Aug 04 2011
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