OFFSET
0,3
LINKS
Michael De Vlieger, Table of n, a(n) for n = 0..10000
Mike Winkler, The algorithmic structure of the finite stopping time behavior of the 3x+ 1 function, arXiv:1709.03385 [math.GM], 2017.
FORMULA
a(n) = A020914(n) - 1. - L. Edson Jeffery, Dec 12 2014
EXAMPLE
a(3)=4 because 3^3=27 and 2^4=16 is power of 2 immediately below 27.
MAPLE
seq(ilog2(3^n), n= 0 .. 1000); # Robert Israel, Dec 11 2014
MATHEMATICA
Table[Floor[Log[2, 3^n]], {n, 0, 69}] (* Robert G. Wilson v, Apr 06 2006 *)
Table[Floor[n*Log[2, 3]], {n, 0, 68}] (* L. Edson Jeffery, Dec 11 2014 *)
PROG
(PARI) {a(n) = if( n<0, 0, logint(3^n, 2))}; /* Michael Somos, Dec 13 2014 */
(Haskell)
a056576 = subtract 1 . a020914 -- Reinhard Zumkeller, May 17 2015
(Python)
def A056576(n): return (3**n).bit_length()-1 # Chai Wah Wu, Oct 09 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Henry Bottomley, Jun 29 2000
STATUS
approved