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 A168299 #21 Sep 08 2022 08:45:49
%S A168299 1,4,73,730,5185,30376,157465,750142,3359233,14348908,59049001,
%T A168299 235782658,918330049,3502727632,13124466937,48427561126,176319369217,
%U A168299 634465620820,2259436291849,7971951402154,27894275208001,96873331012984
%N A168299 a(n) = 1 + 3^n * n^3.
%C A168299 Numerator of 3^(-n) + n^3.
%H A168299 Vincenzo Librandi, <a href="/A168299/b168299.txt">Table of n, a(n) for n = 0..1000</a>
%F A168299 From _R. J. Mathar_, Nov 24 2009: (Start)
%F A168299 a(n) = 1 + A062074(n).
%F A168299 G.f.: (1 -9*x +87*x^2 -117*x^3 +54*x^4)/((1-x)*(3*x-1)^4). (End)
%F A168299 E.g.f.: exp(x) + 3*x*(1 + 9*x + 9*x^2)*exp(3*x). - _G. C. Greubel_, Jul 17 2016
%t A168299 f[n_]:=3^n-n^3; Table[Numerator[f[n]],{n,0,-50,-1}]
%o A168299 (Magma) [1+n^3*3^n: n in [0..30]]; // _Vincenzo Librandi_, Jul 02 2011
%o A168299 (PARI) for(n=0,100,print1(1+(n^3)*(3^n),",")) \\ _Edward Jiang_, Nov 22 2013
%Y A168299 Cf. A024026.
%K A168299 nonn,easy
%O A168299 0,2
%A A168299 _Vladimir Joseph Stephan Orlovsky_, Nov 22 2009
%E A168299 Corrected offset, and simplified the definition - _R. J. Mathar_, Nov 24 2009