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%I #34 Mar 15 2023 14:03:18
%S 1,3,5,23,39,181,307,1425,2417,11219,19029,88327,149815,695397,
%T 1179491,5474849,9286113,43103395,73109413,339352311,575589191,
%U 2671715093,4531604115,21034368433,35677243729,165603232371,280886345717,1303791490535,2211413522007
%N x-values in the solution to 15*x^2 - 14 = y^2.
%C When are both n+1 and 15*n+1 perfect squares? This problem gives the equation 15*x^2-14 = y^2.
%C Values of x (or y) in the solutions to x^2 - 8xy + y^2 + 14 = 0. - _Colin Barker_, Feb 05 2014
%H Vincenzo Librandi, <a href="/A199336/b199336.txt">Table of n, a(n) for n = 1..250</a>
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,8,0,-1).
%F a(n+4) = 8*a(n+2) - a(n), a(1)=1, a(2)=3, a(3)=5, a(4)=23.
%F G.f.: x*(1-x)*(1+4*x+x^2)/(1-8*x^2+x^4). - _Bruno Berselli_, Nov 08 2011
%t LinearRecurrence[{0, 8, 0, -1}, {1, 3, 5, 23}, 50] (* _T. D. Noe_, Nov 07 2011 *)
%o (Magma) m:=29; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!((1-x)*(1+4*x+x^2)/(1-8*x^2+x^4))); // _Bruno Berselli_, Nov 08 2011
%Y Cf. A198947, A199338.
%Y Essentially the second differences of A237262. Cf. also A322780.
%K nonn,easy
%O 1,2
%A _Sture Sjöstedt_, Nov 05 2011
%E More terms from _T. D. Noe_, Nov 07 2011
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