OFFSET
1,1
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..10000
FORMULA
EXAMPLE
A066669(9) = 23, phi(23) = 2*11, so a(9)=11.
MATHEMATICA
Select[Array[#/2^IntegerExponent[#, 2] &@ EulerPhi@ # &, 200], PrimeQ] (* Michael De Vlieger, Dec 08 2018 *)
PROG
(PARI) lista(nn) = {for (n=1, nn, en=eulerphi(n); if (isprime(p=en>>valuation(en, 2)), print1(p, ", ")); ); } \\ Michel Marcus, Dec 08 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Dec 18 2001
STATUS
approved