A018068 - OEIS

%I #17 Dec 29 2020 02:51:41

%S 1,2,3,5,8,14,23,39,64,108,182,305,512,862,1449,2436,4096,6889,11586,

%T 19484,32768,55109,92682,155872,262144,440872,741456,1246975,2097152,

%U 3526976,5931642,9975793,16777216

%N Powers of fourth root of 8 rounded up.

%H Robert Israel, <a href="/A018068/b018068.txt">Table of n, a(n) for n = 0..4424</a>

%F a(n) = ceiling(8^(n/4)). - _Michel Marcus_, Dec 28 2020

%p seq(ceil(8^(n/4)),n=0..40); # _Robert Israel_, Dec 28 2020

%o (PARI) a(n) = n*=3; if(n%2,sqrtnint(1<<n,4)+1, n%4,sqrtint(1<<(n/2))+1, 1<<(n/4)); \\ _Kevin Ryde_, Dec 29 2020

%Y Cf. A001018 (powers of 8).

%K nonn

%O 0,2

%A _N. J. A. Sloane_.