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 A138473 #25 Sep 08 2022 08:45:33 %S A138473 0,21,987,46368,2178309,102334155,4807526976,225851433717, %T A138473 10610209857723,498454011879264,23416728348467685,1100087778366101931, %U A138473 51680708854858323072,2427893228399975082453,114059301025943970552219,5358359254990966640871840 %N A138473 a(n) = Fibonacci(8*n). %H A138473 Colin Barker, <a href="/A138473/b138473.txt">Table of n, a(n) for n = 0..500</a> %H A138473 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (47,-1). %F A138473 a(n) = Fibonacci(4*n)*Lucas(4*n) = 21*A049668(n). %F A138473 G.f.: 21*x / ( 1-47*x+x^2 ). - _R. J. Mathar_, Sep 30 2013 %F A138473 From _Colin Barker_, Apr 06 2017: (Start) %F A138473 a(n) = (47 + 21*sqrt(5))^(1-n)*(-2^n+(2207 + 987*sqrt(5))^n) / (105 + 47*sqrt(5)). %F A138473 a(n) = 47*a(n-1) - a(n-2) for n > 1. %F A138473 (End) %t A138473 Fibonacci[8Range[0,20]] (* _Harvey P. Dale_, Jun 22 2013 *) %o A138473 (MuPAD) numlib::fibonacci(8*n) $ n = 0..25; %o A138473 (Sage) [fibonacci(8*n) for n in range(0, 15)] # _Zerinvary Lajos_, May 15 2009 %o A138473 (Magma) [Fibonacci(8*n): n in [0..100]]; // _Vincenzo Librandi_, Apr 17 2011 %o A138473 (PARI) concat(0, Vec(21*x / (1 - 47*x + x^2) + O(x^30))) \\ _Colin Barker_, Apr 06 2017 %Y A138473 Cf. A000032, A000045, A049668, A134498. %K A138473 nonn,easy %O A138473 0,2 %A A138473 _Zerinvary Lajos_, May 09 2008