A365368 -id:A365368 - cp's OEIS frontend

A365369 A365368/5, except when A365368(n) = -1, then a(n) = -1.

1, 1, 1, 4, 2049, 2, 4, 2049, 3, 26, 6, 4, 2049, 21, 5, 9, 26, 6, 49, 11, 7, 2049, 21, 8, 14, 24, 9, 26, 16, 10, 29, 49, 11, 19, 54, 12, 2049, 21, 13, 104, 174, 14, 24, 521, 15, 71, 26, 16, 76, 46, 17, 29, 49, 18, 51, 31, 19, 54, 151, 20, 34, 2049, 21, 99, 36

Offset: 1

Chai Wah Wu, Sep 02 2023

nonn

Cf. A087704, A087705, A087706, A087707, A087708, A087709, A365341, A365342, A365367, A365368.

from fractions import Fraction
def A365369(n):
    x = Fraction(n)
    while x.denominator > 1 or x<=n:
        x = Fraction(5*x._round_(),3)
    return int(x)//5

A365370 Positions of records in A365367.

Original entry on oeis.org

1, 5, 415, 635, 15935, 60971, 275039, 514661, 2857994, 14179544, 170794880, 2382918520

Offset: 1

Chai Wah Wu, Sep 02 2023

nonn

Numbers k such that iteration of the map x -> (5/3)*round(x) starting at x = k takes more steps to reach an integer > k than it does for any number from 1 to k - 1.