A017912 Powers of sqrt(2) rounded up.

1, 2, 2, 3, 4, 6, 8, 12, 16, 23, 32, 46, 64, 91, 128, 182, 256, 363, 512, 725, 1024, 1449, 2048, 2897, 4096, 5793, 8192, 11586, 16384, 23171, 32768, 46341, 65536, 92682, 131072, 185364, 262144, 370728, 524288, 741456, 1048576, 1482911, 2097152, 2965821, 4194304

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Formula

a(n) = A003059(A000079(n)). - Jason Kimberley, Oct 28 2016

a(n) = A017910(n)+1 if n is odd. a(n) = A017910(n) = 2^(n/2) if n is even. - Chai Wah Wu, Jul 26 2022

Mathematica

Ceiling[(Sqrt[2])^Range[0, 40]] (* Vincenzo Librandi, Nov 20 2011 *)

Prog

(Magma) [Ceiling(Sqrt(2^n)): n in [0..40]]; // Vincenzo Librandi, Nov 20 2011
(Python)
from math import isqrt
def A017912(n): return isqrt(1<<n)+1 if n&1 else 1<<(n>>1) # Chai Wah Wu, Jul 26 2022

Crossrefs

Cf. A017910, A329202.

Sequence in context: A334626 A339235 A332755 * A102543 A173383 A316076

Adjacent sequences: A017909 A017910 A017911 * A017913 A017914 A017915

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved