A116779 - OEIS

%I #7 Jul 07 2017 06:21:29

%S 1,2,6,21,72,237,761,2415,7626,24034,75689,238298,750179,2361533,

%T 7433917,23401274,73664906,231889749,729965584,2297858029,7233425149,

%U 22770092131,71677951146,225634953382,710276052265,2235877300106

%N Number of permutations of length n which avoid the patterns 2143, 2341, 3214.

%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_05">Index entries for linear recurrences with constant coefficients</a>, signature (6,-12,11,-5,1).

%F G.f.: A(x) = -{(x^4-2x^3+6x^2-4x+1)x}/{(x-1)^2(x^3-3x^2+4x-1)}

%K nonn,easy

%O 1,2

%A _Lara Pudwell_, Feb 26 2006