A365368 First integer > n reached under iteration of map x -> (5/3)*round(x) when started at n, or -1 if no such integer is ever reached.

5, 5, 5, 20, 10245, 10, 20, 10245, 15, 130, 30, 20, 10245, 105, 25, 45, 130, 30, 245, 55, 35, 10245, 105, 40, 70, 120, 45, 130, 80, 50, 145, 245, 55, 95, 270, 60, 10245, 105, 65, 520, 870, 70, 120, 2605, 75, 355, 130, 80, 380, 230, 85, 145, 245, 90, 255, 155, 95

Offset

1,1

Comments

Conjecture: an integer will always be reached, i.e. a(n) > 0 for all n.

Links

Table of n, a(n) for n=1..57.

Prog

(Python)
from fractions import Fraction
def A365368(n):
    x = Fraction(n)
    while x.denominator > 1 or x<=n:
        x = Fraction(5*x.__round__(), 3)
    return int(x)

Crossrefs

Cf. A087704, A087705, A087706, A087707, A087708, A087709, A365341, A365342, A365367.

Sequence in context: A013607 A260960 A283711 * A098526 A262122 A216876

Adjacent sequences: A365365 A365366 A365367 * A365369 A365370 A365371

Keyword

nonn

Author

Chai Wah Wu, Sep 02 2023

Status

approved