%I #15 Sep 28 2023 09:52:28
%S 1,20,267,3010,31073,304920,2901319,27075950,249555405,2281579300,
%T 20749095731,188036746170,1700122392697,15347941075760,
%U 138412864844703,1247405586235270,11236794818538149,101192043527859900
%N Expansion of 1/((1-x)(1-4x)(1-6x)(1-9x)).
%H Vincenzo Librandi, <a href="/A021824/b021824.txt">Table of n, a(n) for n = 0..200</a>
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (20, -133, 330, -216).
%F G.f.: 1/((1-x)(1-4x)(1-6x)(1-9x)).
%F a(n) = (9^(n+3) - 4*6^(n+3) + 4^(n+4) - 1)/120. - _Yahia Kahloune_, Jul 05 2013
%t CoefficientList[Series[1 / ((1 - x) (1 - 4 x) (1 - 6 x) (1 - 9 x)), {x, 0, 20}], x] (* _Vincenzo Librandi_, Jul 11 2013 *)
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_.