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 A165443 #21 Sep 08 2022 08:45:47
%S A165443 1,5521,35957041,235845988561,1547368082644081,10152277523461827601,
%T A165443 66609091687940958003121,437022250271846649679394641,
%U A165443 2867302983958645970747063186161,18812374877733491600234823630721681
%N A165443 a(n) = ( 16^(2*n+1) + 81^(2*n+1) )/97.
%C A165443 The general form of the g.f. for (A^(2*n+1)+B^(2*n+1))/(A+B) is (1-A*B*x)/((1-A^2*x)(1-B^2*x)).
%H A165443 G. C. Greubel, <a href="/A165443/b165443.txt">Table of n, a(n) for n = 0..260</a>
%H A165443 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (6817,-1679616).
%F A165443 G.f.: (1 - 16*81*x)/((1 - 16^2*x)*(1 - 81^2*x)).
%F A165443 a(n) = (16^2+81^2)*a(n-1) - 16^2*81^2*a(n-2).
%e A165443 a(0) = (16^1 + 81^1)/97 = 97/97 = 1.
%e A165443 a(1) = (16^3 + 81^3)/97 = 535537/97 = 5521.
%p A165443 seq(coeff(series((1-16*81*x)/((1-16^2*x)*(1-81^2*x)),x,n+1), x, n), n = 0 .. 10); # _Muniru A Asiru_, Oct 21 2018
%t A165443 f[n_]:=Module[{c=2n+1},(16^c+81^c)/97]; Array[f,20,0] (* _Harvey P. Dale_, Oct 02 2012 *)
%o A165443 (PARI) a(n)=(16^(2*n+1)+81^(2*n+1))/97
%o A165443 (Magma) [(2^(8*n+4) + 3^(8*n+4))/97: n in [0..20]]; // _G. C. Greubel_, Oct 20 2018
%o A165443 (GAP) List([0..10],n->(16^(2*n+1)+81^(2*n+1))/97); # _Muniru A Asiru_, Oct 21 2018
%o A165443 (Python) for n in range(0, 10): print(int((16**(2*n+1)+81**(2*n+1))/97), end=', ') # _Stefano Spezia_, Oct 21 2018
%Y A165443 Cf. A007689, A082101, A096951, A165259.
%K A165443 nonn,easy
%O A165443 0,2
%A A165443 _Jaume Oliver Lafont_, Sep 19 2009
%E A165443 Definition replaced with formula by _R. J. Mathar_, Sep 21 2009