A116738 - OEIS

%I #9 Nov 08 2017 09:42:23

%S 1,2,6,21,74,260,913,3206,11258,39533,138822,487480,1711809,6011098,

%T 21108254,74122629,260285106,914003420,3209566097,11270542654,

%U 39577041842,138976648157,488023051598,1713715951920,6017794352641

%N Number of permutations of length n which avoid the patterns 3214, 4123, 4132.

%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 142.

%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_03">Index entries for linear recurrences with constant coefficients</a>, signature (4,-2,1).

%F G.f.: A(x) = {x(2x-1)}/{x^3-2x^2+4x-1}

%K nonn,easy

%O 1,2

%A _Lara Pudwell_, Feb 26 2006