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 A145121 #19 Oct 02 2024 07:53:41
%S A145121 361,108661,32815261,9910100161,2992817433361,903820954774861,
%T A145121 272950935524574661,82430278707466772761,24893671218719440799161,
%U A145121 7517806277774563654573861,2270352602216699504240506861,685638968063165475716978498161,207060698002473756967023265937761
%N A145121 Numbers n such that there exists x in N : (x+19)^3-x^3=n^2.
%H A145121 Vincenzo Librandi, <a href="/A145121/b145121.txt">Table of n, a(n) for n = 1..200</a>
%H A145121 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (302,-1).
%F A145121 a(n+2) = 302*a(n+1)-a(n).
%F A145121 a(n) = 361*A145123(n). - _Colin Barker_, Oct 19 2014
%F A145121 G.f.: -361*x*(x-1) / (x^2-302*x+1). - _Colin Barker_, Oct 19 2014
%e A145121 a(1)=361 because 57^3-38^3=361^2.
%t A145121 CoefficientList[Series[361 (1 - x)/(x^2 - 302 x + 1), {x, 0, 20}], x] (* _Vincenzo Librandi_, Oct 19 2014 *)
%o A145121 (PARI) Vec(-361*x*(x-1)/(x^2-302*x+1) + O(x^20)) \\ _Colin Barker_, Oct 19 2014
%o A145121 (Magma) I:=[361,108661]; [n le 2 select I[n] else 302*Self(n-1)-Self(n-2): n in [1..15]]; // _Vincenzo Librandi_, Oct 19 2014
%K A145121 easy,nonn
%O A145121 1,1
%A A145121 _Richard Choulet_, Oct 02 2008
%E A145121 Editing and more terms from _Colin Barker_, Oct 19 2014