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%I #20 Sep 08 2022 08:44:37
%S 0,0,0,0,1,4,9,16,25,38,55,76,101,132,168,210,258,313,376,447,526,613,
%T 710,817,934,1061,1200,1350,1512,1686,1873,2074,2289,2518,2761,3020,
%U 3295,3586,3893,4218,4560,4920,5298,5695,6112,6549,7006,7483
%N a(n) = floor(n*(n-1)*(n-2)/13).
%H Vincenzo Librandi, <a href="/A011895/b011895.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_16">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1,0,0,0,0,0,0,0,0,0,1,-3,3,-1).
%F a(n) = +3*a(n-1) -3*a(n-2) +a(n-3) +a(n-13) -3*a(n-14) +3*a(n-15) -a(n-16). -_R. J. Mathar_, Apr 15 2010
%F G.f.: x^4*(1 +x +2*x^5 +2*x^9 -x^10 +x^11)/((1 -x)^4*(1 +x +x^2 +x^3 +x^4 +x^5 +x^6 +x^7 +x^8 +x^9 +x^10 +x^11 +x^12)). - _Colin Barker_, Sep 07 2016
%o (Magma) [n*(n-1)*(n-2) div 13: n in [0..50]]; // _Vincenzo Librandi_, Sep 07 2016
%o (PARI) concat(vector(4), Vec(x^4*(1 +x +2*x^5 +2*x^9 -x^10 +x^11) / ((1 -x)^4*(1 +x +x^2 +x^3 +x^4 +x^5 +x^6 +x^7 +x^8 +x^9 +x^10 +x^11 +x^12)) + O(x^50))) \\ _Colin Barker_, Sep 07 2016
%K nonn,easy
%O 0,6
%A _N. J. A. Sloane_
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