OFFSET
1,4
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
n=100,p(100)=541, Phi-iteration chain is {541,540,144,48,16,8,4,2,1} with 9 terms. The first 4 terms (541,540,144,48) are not powers of 2, som a(100)=4.
MATHEMATICA
Table[Count[FixedPointList[EulerPhi[#]&, Prime[n]], _?(!IntegerQ[ Log[ 2, #]]&)], {n, 110}] (* Harvey P. Dale, Sep 18 2016 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Labos Elemer, Apr 13 2001
EXTENSIONS
Definition clarified by Harvey P. Dale, Sep 18 2016
STATUS
approved