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 A011938 #26 Oct 27 2024 09:26:12
%S A011938 0,0,0,0,0,4,12,30,60,108,180,282,424,612,858,1170,1560,2040,2622,
%T A011938 3322,4152,5130,6270,7590,9108,10842,12814,15042,17550,20358,23490,
%U A011938 26970,30822,35074,39750,44880,50490,56610,63270,70500,78334,86802,95940,105780
%N A011938 a(n) = floor( n*(n-1)*(n-2)*(n-3)/28 ).
%H A011938 Colin Barker, <a href="/A011938/b011938.txt">Table of n, a(n) for n = 0..1000</a>
%H A011938 <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1,0,0,1,-4,6,-4,1).
%F A011938 a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) + a(n-7) - 4*a(n-8) + 6*a(n-9) - 4*a(n-10) + a(n-11). - _Chai Wah Wu_, May 25 2016
%F A011938 G.f.: 2*x^5*(2-2*x+3*x^2-2*x^3+2*x^4) / ((1-x)^5*(1+x+x^2+x^3+x^4+x^5+x^6)). - _Colin Barker_, May 25 2016
%t A011938 Table[Floor[n (n-1)(n-2)(n-3)/28], {n, 0, 50}] (* _Vincenzo Librandi_, May 27 2016 *)
%t A011938 LinearRecurrence[{4,-6,4,-1,0,0,1,-4,6,-4,1},{0,0,0,0,0,4,12,30,60,108,180}, 50] (* _Harvey P. Dale_, Aug 10 2024 *)
%o A011938 (PARI) concat(vector(5), Vec(2*x^5*(2-2*x+3*x^2-2*x^3+2*x^4)/((1-x)^5*(1+x+x^2+x^3+x^4+x^5+x^6)) + O(x^50))) \\ _Colin Barker_, May 25 2016
%o A011938 (Magma) [Floor(n*(n-1)*(n-2)*(n-3)/28): n in [0..50]]; // _Vincenzo Librandi_, May 27 2016
%o A011938 (SageMath) [6*binomial(n,4)//7 for n in range(61)] # _G. C. Greubel_, Oct 27 2024
%Y A011938 Cf. A011915.
%K A011938 nonn,easy
%O A011938 0,6
%A A011938 _N. J. A. Sloane_