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 A199772 #23 Jan 05 2016 17:08:04
%S A199772 1,4,25,41,260,1649,2705,17156,108809,178489,1132036,7179745,11777569,
%T A199772 74697220,473754361,777141065,4928884484,31260608081,51279532721,
%U A199772 325231678724,2062726378985,3383672018521,21460361911300,136108680404929,223271073689665
%N A199772 x-values in the solution to 17*x^2 - 16 = y^2.
%C A199772 When are both n+1 and 17*n+1 perfect squares? This problem gives the equation 17*x^2-16=y^2.
%H A199772 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,66,0,0,-1).
%F A199772 a(n) = 66*a(n-3) - a(n-6), a(1)=1, a(2)=4, a(3)=25, a(4)=41, a(5)=260, a(6)=1649.
%F A199772 G.f.: -x*(x-1)*(x^4+5*x^3+30*x^2+5*x+1) / (x^6-66*x^3+1). - _Colin Barker_, Sep 01 2013
%e A199772 a(7) = 66*41-1 = 2705.
%t A199772 LinearRecurrence[{0,0,66,0,0,-1}, {1,4,25,41,260,1649}, 50]
%o A199772 (PARI) Vec(-x*(x-1)*(x^4+5*x^3+30*x^2+5*x+1)/(x^6-66*x^3+1) + O(x^100)) \\ _Colin Barker_, Sep 01 2013
%Y A199772 Cf. A199773, A199774, A199798.
%K A199772 nonn,easy
%O A199772 1,2
%A A199772 _Sture Sjöstedt_, Nov 10 2011
%E A199772 More terms from _T. D. Noe_, Nov 10 2011