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 A237262 #34 Sep 06 2020 14:20:56
%S A237262 1,2,6,15,47,118,370,929,2913,7314,22934,57583,180559,453350,1421538,
%T A237262 3569217,11191745,28100386,88112422,221233871,693707631,1741770582,
%U A237262 5461548626,13712930785,42998681377,107961675698,338527902390,849980474799,2665224537743
%N A237262 Values of x in the solutions to x^2 - 8*x*y + y^2 + 11 = 0, where 0 < x < y.
%C A237262 The corresponding values of y are given by a(n+2).
%C A237262 Also values of y in the solutions to the negative Pell equation x^2 - 15*y^2 = -11. - _Colin Barker_, Jan 25 2017
%H A237262 Colin Barker, <a href="/A237262/b237262.txt">Table of n, a(n) for n = 1..1000</a>
%H A237262 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,8,0,-1).
%F A237262 G.f.: -x*(x-1)*(x^2 + 3*x + 1) / (x^4 - 8*x^2 + 1).
%F A237262 a(n) = 8*a(n-2) - a(n-4) for n > 4.
%F A237262 a(n) = (11*a(n-1) - 4*a(n-2))/3 if n is odd; a(n) = (11*a(n-1) - 3*a(n-2))/4 if n is even. - _R. J. Mathar_, Jun 18 2014
%e A237262 6 is a term because (x, y) = (6, 47) is a solution to x^2 - 8xy + y^2 + 11 = 0.
%t A237262 LinearRecurrence[{0,8,0,-1},{1,2,6,15},30] (* _Harvey P. Dale_, Sep 06 2020 *)
%o A237262 (PARI) Vec(-x*(x-1)*(x^2+3*x+1)/(x^4-8*x^2+1) + O(x^100))
%Y A237262 Cf. A001091, A070997, A199336, A281584.
%Y A237262 For first and second differences see A322780, A199336.
%K A237262 nonn,easy
%O A237262 1,2
%A A237262 _Colin Barker_, Feb 05 2014