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 A157112 #21 Sep 08 2022 08:45:41
%S A157112 285769,8478963,27975201,58774483,100876809,154282179,218990593,
%T A157112 295002051,382316553,480934099,590854689,712078323,844605001,
%U A157112 988434723,1143567489,1310003299,1487742153,1676784051,1877128993,2088776979,2311728009
%N A157112 a(n) = 5651522*n^2 - 8761372*n + 3395619.
%C A157112 The identity (5651522*n^2 - 8761372*n + 3395619)^2 - (1681*n^2 - 2606*n + 1010)*(137842*n - 106846)^2 = 1 can be written as a(n)^2 - A157110(n)*A157111(n)^2 = 1. - _Vincenzo Librandi_, Jan 25 2012
%H A157112 Vincenzo Librandi, <a href="/A157112/b157112.txt">Table of n, a(n) for n = 1..10000</a>
%H A157112 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A157112 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - _Vincenzo Librandi_, Jan 25 2012
%F A157112 G.f.: x*(-285769 - 7621656*x - 3395619*x^2)/(x-1)^3. - _Vincenzo Librandi_, Jan 25 2012
%t A157112 LinearRecurrence[{3,-3,1},{285769,8478963,27975201},40] (* _Vincenzo Librandi_, Jan 25 2012 *)
%o A157112 (Magma) I:=[285769, 8478963, 27975201]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..40]]; // _Vincenzo Librandi_, Jan 25 2012
%o A157112 (PARI) for(n=1, 22, print1(5651522*n^2 - 8761372*n + 3395619", ")); \\ _Vincenzo Librandi_, Jan 25 2012
%Y A157112 Cf. A157110, A157111.
%K A157112 nonn,easy
%O A157112 1,1
%A A157112 _Vincenzo Librandi_, Feb 23 2009