OFFSET
2,1
COMMENTS
It is conjectured that an integer is always reached.
LINKS
Robert Israel, Table of n, a(n) for n = 2..10000
FORMULA
a(n) = a(n + m) if a(n) > 0 and m is a (positive or negative) multiple of 3^a(n). - Robert Israel, Sep 01 2023
MAPLE
f2 := proc(x, y) x*floor(y); end; r := 5/3; h := proc(x) local n, y; global r; y := f2(r, x); for n from 1 to 20 do if whattype(y) = 'integer' then RETURN([x, n, y]); else y := f2(r, y); fi; od: RETURN(['NULL', 'NULL', 'NULL']); end; [seq(h(n)[2], n=2..60)];
PROG
(Python)
from fractions import Fraction
def A087704(n):
x, c = Fraction(n, 1), 0
while x.denominator > 1 or x<=n:
x = Fraction(5*x.__floor__(), 3)
c += 1
return c # Chai Wah Wu, Sep 01 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 29 2003
STATUS
approved