OFFSET
2,1
COMMENTS
It appears that all n end in one of the orbits (6,12,16) or (20,24) or one of the fixed points 4, 90, 120, verified to n=10^8.
LINKS
Lars Blomberg, Table of n, a(n) for n = 2..10000
EXAMPLE
For n=2: 2=2^1 -> (2+1)=3=3^1 -> (3+1)=4=2^2 -> (2+2)=4; 4 is repeated so a(2)=3.
For n=12: 12=2^2*3^1 -> (2+2)*(3+1)=16=2^4 -> (2+4)=6=2^1*3^1 -> (2+1)*(3+1)=12; 12 is repeated so a(12)=3.
CROSSREFS
KEYWORD
nonn
AUTHOR
Lars Blomberg, Feb 07 2018
STATUS
approved