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%I #25 Sep 08 2022 08:44:37
%S 0,0,0,0,1,4,8,14,22,33,48,66,88,114,145,182,224,272,326,387,456,532,
%T 616,708,809,920,1040,1170,1310,1461,1624,1798,1984,2182,2393,2618,
%U 2856,3108,3374,3655,3952,4264,4592
%N a(n) = floor(n*(n-1)*(n-2)/15).
%H Vincenzo Librandi, <a href="/A011897/b011897.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1,0,1,-3,3,-1). [From _R. J. Mathar_, Apr 15 2010]
%F From _R. J. Mathar_, Apr 15 2010:
%F a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) + a(n-5) - 3*a(n-6) + 3*a(n-7) - a(n-8).
%F G.f.: x^4*(x^3-x^2+x+1) / ( (-1+x)^4*(x^4+x^3+x^2+x+1) ). (End)
%t CoefficientList[Series[x^4(x^3-x^2+x+1)/((-1+x)^4(x^4+x^3+x^2+x+1)),{x,0,45}],x] (* _Harvey P. Dale_, Feb 25 2011 *)
%o (Magma) [Floor(n*(n-1)*(n-2)/15): n in [0..50]]; // _Vincenzo Librandi_, Jul 07 2012
%K nonn,easy
%O 0,6
%A _N. J. A. Sloane_
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