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%I #13 Oct 28 2013 13:30:06
%S 1,1,2,4,10,24,62,156,406,1040,2714,7012,18322,47560,124358,323708,
%T 846766,2208032,5777330,15082372,39469786
%N Number of involutions avoiding the pattern 1342.
%H Miklós Bóna, Cheyne Homberger, Jay Pantone, and Vince Vatter, <a href="http://arxiv.org/abs/1310.7003">Pattern-avoiding involutions: exact and asymptotic enumeration</a>, arxiv:1310.7003, 2013.
%e Of the 26 involutions of length 5, only 14523 and 15342 contain the pattern 1342, so a(5) = 24.
%Y Cf. A000085, A001006, A121704, A230551-A230556.
%K nonn
%O 0,3
%A _Cheyne Homberger_, Oct 23 2013
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