OFFSET
1,2
LINKS
Dov Jarden, Recurring Sequences, Riveon Lematematika, Jerusalem, 1966. [Annotated scanned copy] See p. 67.
MATHEMATICA
a = {}; Do[If[EulerPhi[6k] == EulerPhi[6 k - 2], AppendTo[a, k]], {k, 1000000}]; a (* Vincenzo Librandi, Dec 11 2016 *)
PROG
(Magma) [n: n in [1..2*10^6] | EulerPhi(6*n) eq EulerPhi(6*n-2)]; // Vincenzo Librandi, Dec 11 2016
(PARI) isok(k) = eulerphi(6*k) == eulerphi(6*k-2); \\ Michel Marcus, Dec 11 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 10 2016
EXTENSIONS
More terms from Vincenzo Librandi, Dec 11 2016
STATUS
approved