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 A077411 #11 Sep 08 2022 08:45:07
%S A077411 7,11,59,103,583,1019,5771,10087,57127,99851,565499,988423,5597863,
%T A077411 9784379,55413131,96855367,548533447,958769291,5429921339,9490837543,
%U A077411 53750679943,93949606139,532076878091,930005223847,5267018100967
%N A077411 Combined Diophantine Chebyshev sequences A077409 and A077250.
%C A077411 a(n)^2 - 24*b(n)^2 = 25, with the companion sequence b(n)= A077410(n).
%H A077411 G. C. Greubel, <a href="/A077411/b077411.txt">Table of n, a(n) for n = 0..1000</a>
%H A077411 <a href="/index/Ch#Cheby">Index entries for sequences related to Chebyshev polynomials.</a>
%H A077411 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,10,0,-1).
%F A077411 a(2*k)= A077409(k) and a(2*k+1)= A077250(k), k>=0.
%F A077411 a(n)= sqrt(24*A077410(n)^2 + 25).
%F A077411 G.f.: (1-x)*(7+18*x+7*x^2)/(1-10*x^2+x^4).
%e A077411 59 = a(2) = sqrt(24*A077410(2)^2 + 25) = sqrt(24*12^2 + 25)= sqrt(3481) = 59.
%t A077411 CoefficientList[Series[(1-x)*(7+18*x+7*x^2)/(1-10*x^2+x^4), {x,0,50}], x] (* or *) LinearRecurrence[{0,10,0,-1}, {7,11,59,103}, 30] (* _G. C. Greubel_, Jan 18 2018 *)
%o A077411 (PARI) x='x+O('x^30); Vec((1-x)*(7+18*x+7*x^2)/(1-10*x^2+x^4)) \\ _G. C. Greubel_, Jan 18 2018
%o A077411 (Magma) I:=[7,11,59,103]; [n le 4 select I[n] else 10*Self(n-2) - Self(n-4): n in [1..30]]; // _G. C. Greubel_, Jan 18 2018
%K A077411 nonn,easy
%O A077411 0,1
%A A077411 _Wolfdieter Lang_, Nov 08 2002