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 A077248 #14 Feb 11 2014 05:23:44
%S A077248 2,3,13,22,102,173,803,1362,6322,10723,49773,84422,391862,664653,
%T A077248 3085123,5232802,24289122,41197763,191227853,324349302,1505533702,
%U A077248 2553596653,11853041763,20104423922,93318800402
%N A077248 Combined Diophantine Chebyshev sequences A077246 and A077244.
%C A077248 3*a(n)^2 - 5*b(n)^2 = 7, with the companion sequence b(n)= A077247(n).
%C A077248 Positive values of x (or y) satisfying x^2 - 8xy + y^2 + 35 = 0. - _Colin Barker_, Feb 08 2014
%H A077248 Vincenzo Librandi, <a href="/A077248/b077248.txt">Table of n, a(n) for n = 0..1000</a>
%H A077248 <a href="/index/Ch#Cheby">Index entries for sequences related to Chebyshev polynomials.</a>
%F A077248 a(2*k)= A077246(k) and a(2*k+1)= A077244(k), k>=0.
%F A077248 G.f.: (1-x)*(2+x)*(1+2*x)/(1-8*x^2+x^4).
%e A077248 13 = a(2) = sqrt((5*A077247(2)^2 + 7)/3) = sqrt((5*10^2 + 7)/3)= sqrt(169) = 13.
%t A077248 CoefficientList[Series[(1 - x) (2 + x) (1 + 2 x)/(1 - 8 x^2 + x^4), {x, 0, 30}], x] (* _Vincenzo Librandi_, Feb 11 2014 *)
%K A077248 nonn,easy
%O A077248 0,1
%A A077248 _Wolfdieter Lang_, Nov 08 2002