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 A041067 #29 Jul 09 2025 00:13:17
%S A041067 1,3,37,114,1405,4329,53353,164388,2026009,6242415,76934989,237047382,
%T A041067 2921503573,9001558101,110940200785,341822160456,4212806126257,
%U A041067 12980240539227,159975692596981,492907318330170,6074863512559021,18717497856007233,230684837784645817
%N A041067 Denominators of continued fraction convergents to sqrt(40).
%C A041067 With a(-1) = 0, a(n-1) gives, for n >= 0, the numerator of the convergents to 1/sqrt(40) = 1/(2*sqrt(10)) = A020797. - _Wolfdieter Lang_, Nov 21 2017
%H A041067 Vincenzo Librandi, <a href="/A041067/b041067.txt">Table of n, a(n) for n = 0..200</a>
%H A041067 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (0,38,0,-1).
%F A041067 G.f.: -(x^2-3*x-1) / ((x^2-6*x-1)*(x^2+6*x-1)). - _Colin Barker_, Nov 12 2013
%F A041067 a(n) = 38*a(n-2) - a(n-4). - _Vincenzo Librandi_, Dec 10 2013
%t A041067 Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[40],n]]],{n,1,50}] (* _Vladimir Joseph Stephan Orlovsky_, Mar 21 2011 *)
%t A041067 Denominator[Convergents[Sqrt[40],30]] (* _Harvey P. Dale_, Sep 12 2013 *)
%t A041067 CoefficientList[Series[-(x^2 - 3 x - 1)/((x^2 - 6 x - 1)(x^2 + 6 x - 1)), {x, 0, 30}], x] (* _Vincenzo Librandi_, Dec 10 2013 *)
%o A041067 (Magma) I:=[1, 3, 37, 114]; [n le 4 select I[n] else 38*Self(n-2)-Self(n-4): n in [1..30]]; // _Vincenzo Librandi_, Dec 10 2013
%Y A041067 Cf. A010494, A041066 (numerators).
%K A041067 nonn,cofr,frac,easy
%O A041067 0,2
%A A041067 _N. J. A. Sloane_
%E A041067 More terms from _Colin Barker_, Nov 12 2013