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 A041177 #15 Jul 09 2025 00:23:34
%S A041177 1,1,9,10,189,199,1781,1980,37421,39401,352629,392030,7409169,7801199,
%T A041177 69818761,77619960,1466978041,1544598001,13823762049,15368360050,
%U A041177 290454242949,305822602999,2737035066941,3042857669940,57508473125861,60551330795801,541919119492269
%N A041177 Denominators of continued fraction convergents to sqrt(98).
%H A041177 Vincenzo Librandi, <a href="/A041177/b041177.txt">Table of n, a(n) for n = 0..200</a>
%H A041177 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 198, 0, 0, 0, -1).
%F A041177 G.f.: (1 +x +9*x^2 +10*x^3 -9*x^4 +x^5 -x^6)/(1 -198*x^4 +x^8). - _Vincenzo Librandi_, Dec 12 2013
%F A041177 a(n) = 198*a(n-4) - a(n-8). - _Vincenzo Librandi_, Dec 12 2013
%t A041177 Denominator[Convergents[Sqrt[98], 30]] (* or *) CoefficientList[Series[(1 + x + 9 x^2 + 10 x^3 - 9 x^4 + x^5 - x^6)/(1 - 198 x^4 + x^8), {x, 0, 30}], x] (* _Vincenzo Librandi_, Dec 12 2013 *)
%o A041177 (Magma) I:=[1, 1, 9, 10, 189, 199, 1781, 1980]; [n le 8 select I[n] else 198*Self(n-4)-Self(n-8): n in [1..40]]; // _Vincenzo Librandi_, Dec 12 2013
%Y A041177 Cf. A041176.
%K A041177 nonn,frac,easy
%O A041177 0,3
%A A041177 _N. J. A. Sloane_
%E A041177 More terms from _Vincenzo Librandi_, Dec 12 2013