login
a(n) = floor(3^log_2(n)).
1

%I #10 Jun 21 2020 15:01:43

%S 0,1,3,5,9,12,17,21,27,32,38,44,51,58,65,73,81,89,97,106,115,124,134,

%T 143,154,164,174,185,196,207,219,231,243,255,267,280,292,305,319,332,

%U 346,359,373,388,402,417,431,446,462,477,492,508,524,540,556,573,589

%N a(n) = floor(3^log_2(n)).

%H Harry J. Smith, <a href="/A060419/b060419.txt">Table of n, a(n) for n = 0..1000</a>

%F a(n) = floor(n^log_2(3)) where log_2(3) = 1.58496250...

%t Floor[3^Log2[Range[0,60]]] (* _Harvey P. Dale_, Jun 21 2020 *)

%o (PARI) { default(realprecision, 100); t=1/log(2); for (n=0, 1000, if (n==0, a=0, a=floor(3^(log(n)*t) + 0.0000001)); write("b060419.txt", n, " ", a); ) } \\ _Harry J. Smith_, Jul 04 2009

%Y Cf. A006046 which shares the property that a(2^k)=3^k.

%K nonn

%O 0,3

%A _Henry Bottomley_, Apr 05 2001