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 A140680 #20 Aug 23 2020 14:15:35
%S A140680 0,19,44,75,112,155,204,259,320,387,460,539,624,715,812,915,1024,1139,
%T A140680 1260,1387,1520,1659,1804,1955,2112,2275,2444,2619,2800,2987,3180,
%U A140680 3379,3584,3795,4012,4235,4464,4699,4940,5187,5440,5699
%N A140680 a(n) = n*(3*n+16).
%H A140680 G. C. Greubel, <a href="/A140680/b140680.txt">Table of n, a(n) for n = 0..5000</a>
%H A140680 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A140680 a(n) = 3*n^2 + 16*n.
%F A140680 a(n) = 6*n + a(n-1) + 13 (with a(0)=0). - _Vincenzo Librandi_, Aug 03 2010
%F A140680 E.g.f.: (3*x^2 + 19*x)*exp(x). - _G. C. Greubel_, Jul 20 2017
%t A140680 a[n_]:=Sum[6*i+13, {i, 1, n}]; (* _Vladimir Joseph Stephan Orlovsky_, Dec 04 2008 *)
%t A140680 Table[n(3n+16),{n,0,50}] (* or *) LinearRecurrence[{3,-3,1},{0,19,44},50] (* _Harvey P. Dale_, Aug 23 2020 *)
%o A140680 (PARI) a(n)=n*(3*n+16) \\ _Charles R Greathouse IV_, Jun 17 2017
%Y A140680 Cf. A033428, A045944, A140676, A067725, A140677, A140678, A067707, A140679, A140681, A140689.
%K A140680 nonn,easy
%O A140680 0,2
%A A140680 _Omar E. Pol_, May 22 2008