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 A015240 #16 Jun 01 2017 04:45:33
%S A015240 0,-3,-4,9,48,125,252,441,704,1053,1500,2057,2736,3549,4508,5625,6912,
%T A015240 8381,10044,11913,14000,16317,18876,21689,24768,28125,31772,35721,
%U A015240 39984,44573,49500,54777,60416,66429
%N A015240 a(n) = (2*n - 5)n^2.
%H A015240 Ivan Panchenko, <a href="/A015240/b015240.txt">Table of n, a(n) for n = 0..1000</a>
%H A015240 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).
%F A015240 G.f.: x*(-3 + 8*x + 7*x^2)/(1-x)^4. - _Ivan Panchenko_, Nov 09 2013
%F A015240 From _G. C. Greubel_, Jul 30 2016: (Start)
%F A015240 a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4).
%F A015240 E.g.f.: x*(-3 + x + 2*x^2)*exp(x). (End)
%t A015240 Table[(2*n - 5)n^2, {n,0,25}] (* or *) LinearRecurrence[{4,-6,4,-1},{0, -3, -4, 9},25] (* _G. C. Greubel_, Jul 30 2016 *)
%o A015240 (PARI) a(n)=(2*n-5)*n^2 \\ _Charles R Greathouse IV_, Jul 30 2016
%K A015240 sign,easy
%O A015240 0,2
%A A015240 _N. J. A. Sloane_, Dec 11 1999