A017965 - OEIS

%I #17 Sep 08 2022 08:44:43

%S 1,4,20,89,400,1789,8000,35777,160000,715542,3200000,14310835,

%T 64000000,286216701,1280000000,5724334022,25600000000,114486680448,

%U 512000000000,2289733608960,10240000000000,45794672179196

%N Powers of sqrt(20) rounded to nearest integer.

%H Vincenzo Librandi, <a href="/A017965/b017965.txt">Table of n, a(n) for n = 0..1000</a>

%t Floor[(Sqrt[20]^Range[0,25]+1/2)] (* _Harvey P. Dale_, Aug 08 2011 *)

%o (Magma) [(Floor((Sqrt(20)^n)+1/2)): n in [0..30]]; // _Vincenzo Librandi_, Aug 09 2011

%o (PARI) a(n)=round(sqrt(20)^n) \\ _Charles R Greathouse IV_, Nov 18 2011

%K nonn

%O 0,2

%A _N. J. A. Sloane_