A185590 - OEIS

A185590

Iterate the map in A006369 starting at 44.

44, 59, 79, 105, 70, 93, 62, 83, 111, 74, 99, 66, 44, 59, 79, 105, 70, 93, 62, 83, 111, 74, 99, 66, 44, 59, 79, 105, 70, 93, 62, 83, 111, 74, 99, 66, 44, 59, 79, 105, 70, 93, 62, 83, 111, 74, 99, 66, 44, 59, 79, 105, 70, 93, 62, 83, 111, 74, 99, 66, 44, 59, 79, 105, 70, 93, 62, 83, 111, 74, 99, 66, 44

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Periodic with period length 12.

REFERENCES

A. O. L. Atkin, Comment on Problem 63-13, SIAM Rev., 8 (1966), 234-236.

J. C. Lagarias, ed., The Ultimate Challenge: The 3x+1 Problem, Amer. Math. Soc., 2010; see page 270. (beware of typo: Lagarias says the orbit of 144 (not 44) has period 12.)

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Index entries for sequences related to 3x+1 (or Collatz) problem

MATHEMATICA

f[n_] := If[Mod[n, 3] == 0, 2*n/3, Round[4*n/3]]; a[1] = 44; a[n_] := a[n] = f[a[n - 1]]; Table[a[n], {n, 1, 73}] (* Jean-François Alcover, Jun 10 2013 *)

PROG

(Haskell)

a185590 n = a185590_list !! (n-1)

a185590_list = iterate a006369 44 -- Reinhard Zumkeller, Dec 31 2011

CROSSREFS

Cf. A006369, A028394, A028396, A094328, A094329, A185589.

Trajectories under A006368 and A006369: A180853, A217218, A185590, A180864, A028393, A028394, A094328, A094329, A028396, A028395, A217729, A182205, A223083-A223088, A185589, A185590.

Sequence in context: A116227 A214176 A306116 * A029690 A353538 A220099

Adjacent sequences: A185587 A185588 A185589 * A185591 A185592 A185593

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Feb 04 2011

STATUS

approved