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 A098257 #9 Mar 16 2017 14:12:26 %S A098257 1,531,281960,149720229,79501159639,42214966048080,22416067470370841, %T A098257 11902889611800868491,6320411967798790797880, %U A098257 3356126852011546112805789,1782097038006163187109076079,946290171054420640808806592160 %N A098257 Chebyshev polynomials S(n,531). %C A098257 Used for all positive integer solutions of Pell equation x^2 - 533*y^2 = -4. See A098258 with A098259. %H A098257 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A098257 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (531, -1). %H A098257 <a href="/index/Ch#Cheby">Index entries for sequences related to Chebyshev polynomials.</a> %F A098257 a(n)= S(n, 531)=U(n, 531/2)= S(2*n+1, sqrt(533))/sqrt(533) with S(n, x)=U(n, x/2) Chebyshev's polynomials of the second kind, A049310. S(-1, x)= 0 = U(-1, x). %F A098257 a(n)=531*a(n-1)-a(n-2), n >= 1; a(0)=1, a(1)=531; a(-1):=0. %F A098257 a(n)=(ap^(n+1) - am^(n+1))/(ap-am) with ap := (531+23*sqrt(533))/2 and am := (531-23*sqrt(533))/2 = 1/ap. %F A098257 G.f.: 1/(1-531*x+x^2). %K A098257 nonn,easy %O A098257 0,2 %A A098257 _Wolfdieter Lang_, Sep 10 2004