This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A011912 #34 Oct 19 2024 21:36:49
%S A011912 0,0,0,0,0,2,4,7,11,16,24,33,44,57,72,91,112,136,163,193,228,266,308,
%T A011912 354,404,460,520,585,655,730,812,899,992,1091,1196,1309,1428,1554,
%U A011912 1687,1827,1976,2132,2296,2468,2648,2838,3036,3243,3459,3684,3920,4165,4420,4685,4960,5247,5544,5852,6171,6501,6844,7198,7564,7942,8332,8736,9152,9581,10023,10478,10948
%N A011912 a(n) = floor(n*(n-1)*(n-2)/30).
%H A011912 Vincenzo Librandi, <a href="/A011912/b011912.txt">Table of n, a(n) for n = 0..1000</a>
%H A011912 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1,0,1,-3,3,-1).
%F A011912 From _R. J. Mathar_, Apr 15 2010: (Start)
%F A011912 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 A011912 G.f.: x^5*(2-2*x+x^2) / ( (1-x)^4*(1+x+x^2+x^3+x^4) ). (End)
%p A011912 seq(floor(binomial(n,3)/5), n=0..80); # _Zerinvary Lajos_, Jan 12 2009
%t A011912 Table[Floor[(n(n-1)(n-2))/30],{n,0,80}] (* or *) LinearRecurrence[{3,-3,1,0, 1,-3,3,-1},{0,0,0,0,0,2,4,7},81] (* _Harvey P. Dale_, Jun 20 2011 *)
%t A011912 CoefficientList[Series[x^5*(x^2-2*x+2)/((-1+x)^4*(x^4+x^3+x^2+x+1)),{x,0,80}],x] (* _Vincenzo Librandi_, Jul 07 2012 *)
%o A011912 (Magma) [Floor(n*(n-1)*(n-2)/30): n in [0..80]]; // _Vincenzo Librandi_, Jul 07 2012
%o A011912 (SageMath) [binomial(n,3)//5 for n in range(81)] # _G. C. Greubel_, Oct 19 2024
%Y A011912 Cf. A011886.
%K A011912 nonn,easy
%O A011912 0,6
%A A011912 _N. J. A. Sloane_