%I #17 Aug 24 2023 12:01:54

%S 4,8,21,64,204,682,2340,8192,29127,104857,381300,1398101,5162220,

%T 19173961,71582788,268435456,1010580540,3817748707,14467258260,

%U 54975581388,209430786243,799644820200,3059510616420,11728124029610

%N a(n) = floor(4^n/n).

%H Vincenzo Librandi, <a href="/A129794/b129794.txt">Table of n, a(n) for n = 1..300</a>

%t Table[Floor[4^n/n],{n,25}] (* _Harvey P. Dale_, Jul 24 2011 *)

%o (Magma)[Floor(4^n / n): n in [1..35]]; // _Vincenzo Librandi_, May 08 2011

%o (Python)

%o def A129794(n): return (1<<(n<<1))//n # _Chai Wah Wu_, Aug 24 2023

%Y Cf. A000799, A092763, A053638.

%K nonn

%O 1,1

%A _Mohammad K. Azarian_, May 18 2007