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 A098560 #22 Feb 02 2023 05:03:16
%S A098560 1,8,64,768,12288,245760,5898240,165150720,5284823040,190253629440,
%T A098560 7610145177600,334846387814400,16072626615091200,835776583984742400,
%U A098560 46803488703145574400,2808209322188734464000,179725396620079005696000
%N A098560 Expansion of e.g.f. (1+4*x)/(1-4*x).
%H A098560 G. C. Greubel, <a href="/A098560/b098560.txt">Table of n, a(n) for n = 0..360</a>
%F A098560 a(n) = 2*4^n*n! - 0^n.
%F A098560 a(n+1) = 8*A034177(n).
%F A098560 a(n) - 4*n*a(n-1) = 0. - _R. J. Mathar_, Dec 21 2014
%F A098560 Sum_{n>=0} 1/a(n) = (exp(1/4)+1)/2. - _Amiram Eldar_, Feb 02 2023
%t A098560 s=2;lst={1};Do[s+=n*s+s;AppendTo[lst, s], {n, 2, 5!, 4}];lst (* _Vladimir Joseph Stephan Orlovsky_, Nov 08 2008 *)
%t A098560 With[{nn=20},CoefficientList[Series[(1+4x)/(1-4x),{x,0,nn}],x] Range[0,nn]!] (* or *) Join[{1},Table[2*4^n n!,{n,20}]] (* _Harvey P. Dale_, Jan 16 2012 *)
%o A098560 (PARI) for(n=0, 30, print1(if(n==0,1, 2^(2*n+1)*n!), ", ")) \\ _G. C. Greubel_, Jan 17 2018
%o A098560 (Magma) [1] cat [2^(2*n+1)*Factorial(n): n in [2..30]]; // _G. C. Greubel_, Jan 17 2018
%Y A098560 Cf. A098559, A098558, A032184.
%K A098560 easy,nonn
%O A098560 0,2
%A A098560 _Paul Barry_, Sep 14 2004