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 A017020 #18 Oct 17 2023 19:19:38
%S A017020 81,10000,83521,331776,923521,2085136,4100625,7311616,12117361,
%T A017020 18974736,28398241,40960000,57289761,78074896,104060401,136048896,
%U A017020 174900625,221533456,276922881,342102016,418161601
%N A017020 a(n) = (7*n + 3)^4.
%H A017020 Vincenzo Librandi, <a href="/A017020/b017020.txt">Table of n, a(n) for n = 0..10000</a>
%H A017020 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,10,-5,1).
%F A017020 From _G. C. Greubel_, Oct 17 2023: (Start)
%F A017020 G.f.: (81 + 9595*x + 34331*x^2 + 13361*x^3 + 256*x^4)/(1 - x)^5.
%F A017020 E.g.f.: (81 + 9919*x + 31801*x^2 + 18522*x^3 + 2401*x^4)*exp(x). (End)
%t A017020 (7*Range[0,20]+3)^4 (* or *) LinearRecurrence[{5,-10,10,-5,1},{81,10000,83521,331776,923521},30] (* _Harvey P. Dale_, Oct 29 2019 *)
%o A017020 (Magma) [(7*n+3)^4: n in [0..35]]; // _Vincenzo Librandi_, Jul 14 2011
%o A017020 (SageMath) [(7*n+3)^4 for n in range(41)] # _G. C. Greubel_, Oct 17 2023
%Y A017020 Cf. A017017, A017018, A017019, A017021 - A017028.
%K A017020 nonn,easy
%O A017020 0,1
%A A017020 _N. J. A. Sloane_