OFFSET
1,1
COMMENTS
If n=p*2^k, where k>0 and p is some prime then a(n)=k.
If n is odd then a(n)=a(3n+1)+1.
If n is even then a(n)=1 or a(n)=a(n/2)+1.
If n is composite then a(n)=A274472(n).
LINKS
Dmitry Kamenetsky, Table of n, a(n) for n = 1..10000
EXAMPLE
The Collatz iteration for 33 is 100, 50, 25, 76, 38, 19, 58, 29, ... 1. The first prime (19) is reached after 6 steps, so a(33)=6.
CROSSREFS
KEYWORD
nonn
AUTHOR
Dmitry Kamenetsky, Jan 11 2017
STATUS
approved