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%I #6 Mar 21 2021 21:24:16
%S 1,1,2,6,21,77,284,1041,3789,13730,49679,179906,653083,2378702,
%T 8696754,31921462,117624497,435047541,1614769933,6013417811,
%U 22463101851,84151166305,316084324517,1190187380109,4491810419947,16988382790291,64379012014331,244422429188511,929587527276463
%N Number of permutations of [n] avoiding {1234, 1324, 2341}.
%H D. Callan, T. Mansour, <a href="http://arxiv.org/abs/1705.00933">Enumeration of small Wilf classes avoiding 1324 and two other 4-letter patterns</a>, arXiv:1705.00933 [math.CO] (2017), Table 1 No 211.
%p C := (1-sqrt(1-4*x))/2/x ;
%p ((1 -4*x +5*x^2 -3*x^3)*C -(1 -4*x +6*x^2 -4*x^3))/(x*(1 -x)^2*(1 -2*x)) ;
%p taylor(%,x=0,40) ;
%p gfun[seriestolist](%) ;
%K nonn,easy
%O 0,3
%A _R. J. Mathar_, Nov 09 2017
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