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%I #9 Nov 08 2017 09:38:20
%S 1,2,6,21,74,257,886,3050,10505,36206,124833,430474,1484526,5119597,
%T 17655746,60888801,209985534,724171922,2497434881,8612847430,
%U 29702935745,102435859346,353268294998,1218308608389,4201554149626
%N Number of permutations of length n which avoid the patterns 1423, 2134, 3214.
%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 2 No 140.
%H Lara Pudwell, <a href="http://faculty.valpo.edu/lpudwell/maple/webbook/bookmain.html">Systematic Studies in Pattern Avoidance</a>, 2005.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (7,-17,19,-9).
%F G.f.: A(x) = -{(2x-1)(3x^2-3x+1)x}/{9x^4-19x^3+17x^2-7x+1}
%K nonn,easy
%O 1,2
%A _Lara Pudwell_, Feb 26 2006