OFFSET
1,2
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..6255 (terms below 10^10)
EXAMPLE
6 is included because phi(6) = 2 divides phi(7) = 6.
MATHEMATICA
Select[Range[4000], Divisible[EulerPhi[# + 1], EulerPhi[#]] &] (* Amiram Eldar, Jul 13 2019 *)
PROG
(PARI) lista(nn) = for (n=1, nn, if (eulerphi(n+1) % eulerphi(n) == 0, print1(n, ", "))); \\ Michel Marcus, Sep 14 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Nov 11 2000
EXTENSIONS
Offset set to 1 by Michel Marcus, Sep 14 2015
STATUS
approved