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%I #18 Jun 13 2015 00:51:15
%S 1,4,16,60,215,747,2539,8491,28049,91782,298109,962594,3093687,
%T 9905444,31619072,100681587,319944693,1015039586,3215903436,
%U 10177462312,32179381609,101668695088,321014982282,1013068488800,3195703133266,10077204123667,31767718475161
%N G.f.: (1-x)^5/((-1+4*x-3*x^2+x^3)*(1-3*x+x^2)*(-1+2*x)).
%H Harvey P. Dale, <a href="/A089932/b089932.txt">Table of n, a(n) for n = 0..1000</a>
%H A. Burstein and T. Mansour, <a href="http://arXiv.org/abs/math.CO/0112281">Words restricted by 3-letter generalized multipermutation patterns</a>, Annals. Combin., 7 (2003), 1-14. See Th. 3.6, case k=4.
%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (9,-30,46,-34,13,-2)
%t CoefficientList[Series[(1-x)^5/((-1+4x-3x^2+x^3)(1-3x+x^2)(-1+2x)),{x,0,30}],x] (* or *) LinearRecurrence[{9,-30,46,-34,13,-2},{1,4,16,60,215,747},30] (* _Harvey P. Dale_, May 20 2015 *)
%Y Cf. A061667, A089883, A089947.
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_, Jan 18 2004