OFFSET
0,2
COMMENTS
If the (3x+1)-Collatz conjecture is true, then this sequence is a permutation of the nonnegative integers.
EXAMPLE
a(0)=0. Let m=3. Then f(m)=5, f^2(m)=1. The corresponding numbers n=(m-1)/2 are 1,2,0. By the condition, a(1) > a(2) > a(0)=0. Therefore let a(2)=1, a(1)=2. Furthermore, consider m=7. Then f(m)=11, f^2(m)=17, f^3(m)=13, f^4(m)=5. The corresponding numbers n=(m-1)/2 are 3,5,8,6,2 and, by the condition, a(3) > a(5) > a(8) > a(6) > a(2)=1. Therefore set a(6)=3 (the minimal value which yet did not appear), a(8)=4, a(5)=5, a(3)=6, etc.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Vladimir Shevelev, May 10 2009; corrected May 13 2009, May 19 2009
EXTENSIONS
Name edited by Michel Marcus, Feb 01 2021
STATUS
approved