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%I #24 Mar 21 2021 21:32:26
%S 1,1,2,6,21,77,289,1103,4261,16603,65100,256466,1014107,4021836,
%T 15988827,63691619,254145940,1015570446,4063266013,16274491491,
%U 65245082548,261786577155,1051150840105,4223435727598,16979312455238,68297061505195,274846004875298,1106529463859781
%N Number of permutations of [n] avoiding {2143, 1432, 1324}.
%H Robert Israel, <a href="/A294048/b294048.txt">Table of n, a(n) for n = 0..1646</a>
%H D. Callan and 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 227.
%F D-finite with recurrence (-n+1)*a(n) +3*(4*n-7)*a(n-1) +(-56*n+143)*a(n-2) +6*(23*n-80)*a(n-3) +(-214*n+979)*a(n-4) +9*(24*n-139)*a(n-5) +4*(-35*n+248)*a(n-6) +(49*n-418)*a(n-7) +3*(-n+13)*a(n-8) +2*(-2*n+17)*a(n-9)=0. - _R. J. Mathar_, Mar 11 2021
%p C := (1-sqrt(1-4*x))/2/x ;
%p (1 -6*x +12*x^2 -12*x^3 +6*x^4 -x^5 -x^2*(1 -x +x^2)^2*C)/(1 -7*x +16*x^2 -19*x^3 +11*x^4 -2*x^5 -x^6) ;
%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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