A293332 Least integer k such that k/2^n > sqrt(5).

3, 5, 9, 18, 36, 72, 144, 287, 573, 1145, 2290, 4580, 9159, 18318, 36636, 73272, 146543, 293086, 586172, 1172344, 2344688, 4689375, 9378749, 18757498, 37514996, 75029991, 150059982, 300119964, 600239928, 1200479855, 2400959709, 4801919418, 9603838835

Offset

0,1

Links

Clark Kimberling, Table of n, a(n) for n = 0..1000

Formula

a(n) = ceiling(r*2^n), where r = sqrt(5).

a(n) = A293331(n) + 1.

Mathematica

z = 120; r = Sqrt[5];
Table[Floor[r*2^n], {n, 0, z}];   (* A293331 *)
Table[Ceiling[r*2^n], {n, 0, z}]; (* A293332 *)
Table[Round[r*2^n], {n, 0, z}];   (* A293333 *)

Prog

(Python)
from math import isqrt
def A293332(n): return 1+isqrt(5*(1<<(n<<1))) # Chai Wah Wu, Jul 28 2022

Crossrefs

Cf. A001633, A293331, A293333.

Sequence in context: A288231 A279592 A288229 * A288135 A279634 A028411

Adjacent sequences: A293329 A293330 A293331 * A293333 A293334 A293335

Keyword

nonn,easy

Author

Clark Kimberling, Oct 10 2017

Status

approved