OFFSET
1,2
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
13 is included because phi(14) = 6 divides phi(13) = 12.
MAPLE
for n from 1 to 2000 do
if modp(numtheory[phi](n), numtheory[phi](n+1)) =0 then
printf("%d, ", n) ;
end if;
end do: # R. J. Mathar, Sep 14 2015
MATHEMATICA
Select[Range[1800], Divisible[EulerPhi[#], EulerPhi[# + 1]] &] (* Amiram Eldar, Jul 13 2019 *)
PROG
(PARI) lista(nn) = for (n=1, nn, if (eulerphi(n) % eulerphi(n+1) == 0, print1(n, ", "))); \\ Michel Marcus, Sep 14 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Nov 11 2000
STATUS
approved