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A087665 Consider recurrence b(0) = n/4, b(k) = b(k-1)*floor(b(k-1)); sequence gives first integer reached, or -1 if no integer is ever reached. 2
2, 18, 5, 550935, 3, 3396542576998428, 105 (list; graph; refs; listen; history; text; internal format)
OFFSET
8,1
COMMENTS
It is conjectured that an integer is always reached if the initial value is >= 2.
a(133) has 6227 digits. - Michael S. Branicky, Feb 18 2021
LINKS
Michael S. Branicky, Table of n, a(n) for n = 8..132
J. C. Lagarias and N. J. A. Sloane, Approximate squaring (pdf, ps), Experimental Math., 13 (2004), 113-128.
PROG
(Python)
from fractions import Fraction
def a(n):
b = Fraction(n, 4)
while b.denominator != 1: b *= int(b)
return b
for n in range(8, 15): print(a(n)) # Michael S. Branicky, Feb 18 2021
CROSSREFS
Cf. A087664 (steps to reach an integer), A087667, A087668.
Sequence in context: A253603 A094048 A179073 * A093481 A132629 A288161
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 27 2003
EXTENSIONS
The next term is too large to include.
STATUS
approved

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Last modified March 28 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)