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 A168571 #24 Sep 08 2022 08:45:49
%S A168571 0,25,150,775,3900,19525,97650,488275,2441400,12207025,61035150,
%T A168571 305175775,1525878900,7629394525,38146972650,190734863275,
%U A168571 953674316400,4768371582025,23841857910150,119209289550775,596046447753900,2980232238769525
%N A168571 a(n) = 25*(5^n - 1)/4.
%C A168571 Partial sums of A000351, starting with A000351(2).
%H A168571 Vincenzo Librandi, <a href="/A168571/b168571.txt">Table of n, a(n) for n = 0..1000</a>
%H A168571 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (6,-5).
%F A168571 From _R. J. Mathar_, Jan 04 2011: (Start)
%F A168571 a(n) = 25*A003463(n).
%F A168571 a(n) = +6*a(n-1) -5*a(n-2).
%F A168571 G.f.: 25*x / ( (5*x-1)*(x-1) ). (End)
%F A168571 E.g.f.: (25/4)*(exp(5*x) - exp(x)). - _G. C. Greubel_, Jul 26 2016
%t A168571 CoefficientList[Series[25 x / ((1 - x) (1 - 5 x)), {x, 0, 30}], x] (* _Vincenzo Librandi_, Sep 24 2014 *)
%t A168571 LinearRecurrence[{6,-5}, {0,25}, 25] (* _G. C. Greubel_, Jul 26 2016 *)
%o A168571 (Magma) [25*(5^n-1)/4: n in [0..30]]; // _Vincenzo Librandi_, Sep 24 2014
%o A168571 (PARI) a(n)=25*(5^n-1)/4 \\ _Charles R Greathouse IV_, Jul 26 2016
%K A168571 nonn,easy
%O A168571 0,2
%A A168571 _Vincenzo Librandi_, Nov 30 2009
%E A168571 Definition and examples simplified by _Jon E. Schoenfield_, Jun 19 2010