OFFSET
0,2
EXAMPLE
n=13: 2^n=8192, trajectory ={8192,8191,26208,[20440],.. }, a[13]=3+1=4 with 3 transients and one recurrent term.
MATHEMATICA
EulerPhi[DivisorSigma[1, x]] itef[x_, len_] :=NestList[fs, x, len] Table[Length[Union[itef[2^w, 1000]]], {w, 1, 256}]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Labos Elemer, Jul 21 2004
STATUS
approved