OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..100
FORMULA
If k = 4^j, j >= 0, k is in the sequence.
MATHEMATICA
Select[Range[1000], IntegerQ[Sum[EulerPhi[i]/GCD[#, i], {i, 1, #}]] &] (* Amiram Eldar, Jun 06 2022 *)
PROG
(PARI) isok(n) = type(sum(i=1, n, eulerphi(i)/gcd(n, i))) == "t_INT"; \\ Michel Marcus, Nov 20 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Jan 26 2002
EXTENSIONS
More terms from Michel Marcus, Nov 20 2013
STATUS
approved