%I #21 Jun 13 2015 00:53:30
%S 1,127,32257,8193151,2081028097,528572943487,134255446617601,
%T 34100354867927167,8661355881006882817,2199950293420880308351,
%U 558778713173022591438337,141927593195654317345029247
%N Numbers x such that x^2 - 28*y^2 = 1 for some integer y.
%C This sequence gives the values of x in solutions of the Pell equation x^2 - 28*y^2 = 1; the corresponding y values are in A175672. [Edited by _Jon E. Schoenfield_, May 04 2014]
%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (254,-1).
%F a(n) = 254*a(n-1) - a(n-2) (with a(1)=1, a(2)=127).
%F G.f.: x*(1-127*x)/(1-254*x+x^2). - _Bruno Berselli_, Apr 18 2011
%Y Cf. A175672.
%Y Row 8 of array A188644.
%K nonn
%O 1,2
%A _Vincenzo Librandi_, Dec 04 2010