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Expansion of 1/((1-3x)(1-4x)(1-6x)(1-7x)).
2

%I #19 Sep 29 2022 11:49:43

%S 1,20,255,2650,24521,210840,1725235,13631750,104995341,793395460,

%T 5908353815,43502236050,317443722961,2299938136880,16567618807995,

%U 118785894675550,848393691575381,6040178746163100,42890062369599775,303884399490790250,2149118961443240601

%N Expansion of 1/((1-3x)(1-4x)(1-6x)(1-7x)).

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (20,-145,450,-504).

%F a(n) = (7^(n+3)-2*6^(n+3)+2*4^(n+3)-3^(n+3))/12. - _Yahia Kahloune_, May 30 2013

%F E.g.f.: exp(3*x)*(343*exp(4*x) - 432*exp(3*x) + 128*exp(x) - 27)/12. - _Stefano Spezia_, Sep 29 2022

%t CoefficientList[Series[1/((1-3x)(1-4x)(1-6x)(1-7x)),{x,0,20}],x] (* _Harvey P. Dale_, Jan 09 2019 *)

%Y Cf. A025986, A028027.

%K nonn,easy

%O 0,2

%A _N. J. A. Sloane_