OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Perfect Powers.
Eric Weisstein's World of Mathematics, Totient Function.
MATHEMATICA
powQ[n_] := GCD @@ FactorInteger[n][[;; , 2]] > 1; EulerPhi[Join[{1}, Select[Range[2000], powQ]]] (* Amiram Eldar, Feb 29 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Oct 09 2002
STATUS
approved