A085071 Integers reached in A085068.

0, 4, 4, 4, 8, 84, 8, 84, 20, 12, 84, 20, 16, 24, 84, 20, 40, 56, 24, 84, 36, 28, 40, 56, 32, 148, 84, 36, 68, 52, 40, 56, 104, 44, 148, 84, 48, 120, 68, 52, 72, 132, 56, 104, 452, 60, 148, 84, 64, 88, 120, 68, 168, 404, 72, 132, 100, 76, 104, 452, 80, 196, 148, 84, 872, 116, 88

Offset

0,2

Links

Table of n, a(n) for n=0..66.

J. C. Lagarias and N. J. A. Sloane, Approximate squaring (pdf, ps), Experimental Math., 13 (2004), 113-128.

Maple

a:= proc(n) local i; n; for i do 4/3*ceil(%);
      if %::integer then return % fi od
    end:
seq(a(n), n=0..100);  # Alois P. Heinz, Mar 01 2021

Mathematica

a[n_] := Module[{k = 4n/3}, While[!IntegerQ[k], k = 4* Ceiling[k]/3]; k];
Table[a[n], {n, 0, 100}] (* Jean-François Alcover, Feb 17 2023 *)

Prog

(Python3)
from fractions import Fraction
def A085071(n):
    c, x = 0, Fraction(n, 1)
    while x.denominator > 1 or x <= n:
        x = Fraction(4*x.__ceil__(), 3)
        c += 1
    return x.numerator # Chai Wah Wu, Mar 01 2021

Crossrefs

Sequence in context: A276113 A232406 A322040 * A341324 A011412 A183030

Adjacent sequences: A085068 A085069 A085070 * A085072 A085073 A085074

Keyword

nonn

Author

N. J. A. Sloane, Aug 11 2003

Status

approved