The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #9 Sep 24 2021 08:06:34
%S 1,1,2,6,21,73,238,721,2044,5492,14178,35610,87938,215295,525787,
%T 1286294,3160692,7812235,19435271,48669058,122640467,310825886,
%U 791852703,2026485203,5206520173,13421671869,34697109772,89909564367,233436502611,607059621989,1580760867164,4120657531699
%N Number of permutations of [n] avoiding {1243, 1324, 4231}.
%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 75.
%H <a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (15,-101,404,-1070,1978,-2618,2500,-1709,815,-257,48,-4).
%p x/(1-3*x+x^2) -(2-4*x-4*x^2-x^3) /(1-2*x)^2 +(3 -20*x +55*x^2 -83*x^3 +74*x^4 -38*x^5 +12*x^6 -2*x^7) /(1-x)^8 ;
%p taylor(%,x=0,40) ;
%p gfun[seriestolist](%) ;
%K nonn,easy
%O 0,3
%A _R. J. Mathar_, Nov 09 2017