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 A097765 #9 Aug 12 2015 08:58:14
%S A097765 1,486,236195,114790284,55787841829,27112776338610,13176753512722631,
%T A097765 6403875094406860056,3112270119128221264585,1512556874021221127728254,
%U A097765 735099528504194339854666859,357256858296164427948240365220
%N A097765 Chebyshev U(n,x) polynomial evaluated at x=243=2*11^2+1.
%C A097765 Used to form integer solutions of Pell equation a^2 - 122*b^2 =-1. See A097766 with A097767.
%H A097765 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>
%H A097765 <a href="/index/Ch#Cheby">Index entries for sequences related to Chebyshev polynomials.</a>
%H A097765 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (486, -1).
%F A097765 a(n) = 2*243*a(n-1) - a(n-2), n>=1, a(0)=1, a(-1):=0.
%F A097765 a(n) = S(n, 2*243)= U(n, 243), Chebyshev's polynomials of the second kind. See A049310.
%F A097765 G.f.: 1/(1-486*x+x^2).
%F A097765 a(n)= sum((-1)^k*binomial(n-k, k)*486^(n-2*k), k=0..floor(n/2)), n>=0.
%F A097765 a(n) = ((243+22*sqrt(122))^(n+1) - (243-22*sqrt(122))^(n+1))/(44*sqrt(122)), n>=0.
%t A097765 LinearRecurrence[{486, -1},{1, 486},12] (* _Ray Chandler_, Aug 12 2015 *)
%K A097765 nonn,easy
%O A097765 0,2
%A A097765 _Wolfdieter Lang_, Aug 31 2004