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 A154027 #31 Dec 31 2023 11:36:00
%S A154027 0,10,1000,99990,9998000,999700010,99960003000,9995000599990,
%T A154027 999400099996000,99930014999000010,9992002099800005000,
%U A154027 999100279965001499990,99900035994400349994000,9989004499160069997900010
%N A154027 a(n+2) = 100*a(n+1) - a(n), a(1)=0, a(2)=10.
%C A154027 If a(n)=x and a(n+1)=y then (x^2+y^2)/(xy+1)=100.
%H A154027 Vincenzo Librandi, <a href="/A154027/b154027.txt">Table of n, a(n) for n = 1..200</a>
%H A154027 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (100,-1).
%F A154027 G.f.: (10*x)/(1 -100*x +x^2). - _Harvey P. Dale_, Aug 15 2012
%t A154027 LinearRecurrence[{100,-1},{0,10},20] (* _Vincenzo Librandi_, Feb 26 2012 *)
%t A154027 CoefficientList[Series[(10*x)/(1-100*x+x^2),{x,0,20}],x] (* _Harvey P. Dale_, Aug 15 2012 *)
%o A154027 (Magma) I:=[0, 10]; [n le 2 select I[n] else 100*Self(n-1)-Self(n-2): n in [1..20]]; // _Vincenzo Librandi_, Feb 26 2012
%o A154027 (PARI) a(n)=([0,1;-1,100]^n*[0;10])[1,1] \\ _Charles R Greathouse IV_, Sep 01 2016
%Y A154027 Cf. A065100, A154021-A154026.
%K A154027 nonn,easy
%O A154027 1,2
%A A154027 _Vincenzo Librandi_, Jan 04 2009