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 A175633 #21 Jun 13 2015 00:53:30 %S A175633 1,127,32257,8193151,2081028097,528572943487,134255446617601, %T A175633 34100354867927167,8661355881006882817,2199950293420880308351, %U A175633 558778713173022591438337,141927593195654317345029247 %N A175633 Numbers x such that x^2 - 28*y^2 = 1 for some integer y. %C A175633 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 A175633 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (254,-1). %F A175633 a(n) = 254*a(n-1) - a(n-2) (with a(1)=1, a(2)=127). %F A175633 G.f.: x*(1-127*x)/(1-254*x+x^2). - _Bruno Berselli_, Apr 18 2011 %Y A175633 Cf. A175672. %Y A175633 Row 8 of array A188644. %K A175633 nonn %O A175633 1,2 %A A175633 _Vincenzo Librandi_, Dec 04 2010