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%I #13 Apr 24 2019 11:49:41
%S 1,0,0,0,0,0,0,0,1,0,0,0,1,0,1,0,1,0,1,0,1,0,1,0,0,0,0,0,0,0,1,0,1,0,
%T 0,0,0,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,0,0,1,0,1,0,1,0,1,0,1,0,0,0,
%U 1,0,1,0,1,0,1,0,1,0,0,0,1,0,0,0,0,0,1
%N a(n) = A134664(n) mod 2.
%C It would be nice to have an alternative characterization of this sequence.
%H C. Defant, <a href="https://arxiv.org/abs/1903.09138">Counting 3-stack-sortable permutations</a>, arXiv:1903.09138 [math.CO], 2019.
%H M. Elder and V. Vatter, <a href="https://arxiv.org/abs/math/0505504">Problems and Conjectures presented at the Third International Conference on Permutation Patterns, University of Florida, March 7-11, 2005</a>, arXiv:math/0505504 [math.CO], 2005.
%e There are 114 3-stack-sortable permutations of {1,2,3,4,5}. Since 114 is even, a(5)=0.
%Y Cf. A134664, A324964.
%K nonn
%O 1
%A _Colin Defant_, Mar 18 2019
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