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 A120978 #18 Jul 31 2015 20:33:41
%S A120978 0,4,20,104,552,2892,14908,75952,384080,1933460,9706596,48651000,
%T A120978 243609208,1219108828,6098732684,30503229248,152544843936,
%U A120978 762810312996,3814309845172,19072324066696,95363944856264,476826697849964
%N A120978 2n+5^n-3^n.
%H A120978 Vincenzo Librandi, <a href="/A120978/b120978.txt">Table of n, a(n) for n = 0..1000</a>
%H A120978 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (10, -32, 38, -15).
%F A120978 a(0)=0, a(1)=4, a(2)=20, a(3)=104, a(n) = 10*a(n-1)-32*a(n-2)+38*a(n-3)-15*a(n-4) [_Harvey P. Dale_, Jun 15 2011]
%F A120978 G.f.: 2*x*(2-10*x+16*x^2)/((1-x)^2*(1-5*x)*(1-3*x)). - _Vincenzo Librandi_, Feb 23 2013
%t A120978 Table[2 n + 5^n - 3^n, {n, 0, 30}] (* or *) LinearRecurrence[{10, -32, 38, -15},{0, 4, 20, 104}, 30] (* _Harvey P. Dale_, Jun 15 2011 *)
%t A120978 CoefficientList[Series[2 x (2 - 10 x + 16 x^2)/((1 - x)^2(1 - 5 x)(1 - 3 x)), {x, 0, 30}], x] (* _Vincenzo Librandi_, Feb 23 2013 *)
%Y A120978 Cf. A074606, A005058.
%K A120978 nonn,easy
%O A120978 0,2
%A A120978 _Mohammad K. Azarian_, Aug 19 2006
%E A120978 Edited by _Ray Chandler_, Sep 06 2006