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 A199710 #19 Mar 29 2024 05:43:53
%S A199710 1,1,14,41,223,979,3878,20483,70897,408073,1329734,7964417,25250959,
%T A199710 154039339,482301806,2967115019,9237038497,57046572241,177128072702,
%U A199710 1095861584537,3398526529663,21043253658307,65224098543926,404010494645843,1251923775716881
%N A199710 Expansion of (1+x-14*x^2+13*x^3)/(1-28*x^2+169*x^4).
%H A199710 Bruno Berselli, <a href="/A199710/b199710.txt">Table of n, a(n) for n = 0..1000</a>
%H A199710 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,28,0,-169).
%F A199710 G.f.: (1+x-14*x^2+13*x^3)/(1-28*x^2+169*x^4).
%F A199710 a(n) = ((1+3*sqrt(3))^n+(1-3*sqrt(3))^n)/(2*2^floor(n/2)).
%F A199710 a(n) = 28*a(n-2)-169*a(n-4).
%t A199710 LinearRecurrence[{0, 28, 0, -169}, {1, 1, 14, 41}, 25]
%t A199710 CoefficientList[Series[(1+x-14x^2+13x^3)/(1-28x^2+169x^4),{x,0,30}],x] (* _Harvey P. Dale_, Nov 08 2017 *)
%o A199710 (PARI) Vec((1+x-14*x^2+13*x^3)/(1-28*x^2+169*x^4)+O(x^25))
%o A199710 (Magma) I:=[1,1,14,41]; [n le 4 select I[n] else 28*Self(n-2)-169*Self(n-4): n in [1..25]];
%o A199710 (Maxima) makelist(expand(((1+3*sqrt(3))^n+(1-3*sqrt(3))^n)/(2*2^floor(n/2))),n,0,24);
%Y A199710 Cf. A002531, A083332.
%K A199710 nonn,easy
%O A199710 0,3
%A A199710 _Bruno Berselli_, Nov 10 2011