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 A129794 #17 Aug 24 2023 12:01:54
%S A129794 4,8,21,64,204,682,2340,8192,29127,104857,381300,1398101,5162220,
%T A129794 19173961,71582788,268435456,1010580540,3817748707,14467258260,
%U A129794 54975581388,209430786243,799644820200,3059510616420,11728124029610
%N A129794 a(n) = floor(4^n/n).
%H A129794 Vincenzo Librandi, <a href="/A129794/b129794.txt">Table of n, a(n) for n = 1..300</a>
%t A129794 Table[Floor[4^n/n],{n,25}] (* _Harvey P. Dale_, Jul 24 2011 *)
%o A129794 (Magma)[Floor(4^n / n): n in [1..35]]; // _Vincenzo Librandi_, May 08 2011
%o A129794 (Python)
%o A129794 def A129794(n): return (1<<(n<<1))//n # _Chai Wah Wu_, Aug 24 2023
%Y A129794 Cf. A000799, A092763, A053638.
%K A129794 nonn
%O A129794 1,1
%A A129794 _Mohammad K. Azarian_, May 18 2007