OFFSET
1
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Totient Function
FORMULA
For even n > 2, a(n) = 0. - Iain Fox, Dec 25 2017
If n is in A013929 then a(n) = 0. - David A. Corneth, Dec 25 2017
a(n) = [gcd(n,phi(n)) = 1], where [ ] is the Iverson Bracket. - Wesley Ivan Hurt, Jan 20 2024
EXAMPLE
gcd(5, phi(5)) = gcd(5, 4) = 1, so a(5) = 1.
gcd(6, phi(6)) = gcd(6, 2) = 2, so a(6) = 0.
MATHEMATICA
Table[KroneckerDelta[GCD[n, EulerPhi[n]], 1], {n, 100}] (* Wesley Ivan Hurt, Jan 20 2024 *)
PROG
(PARI) {a(n) = gcd(n, eulerphi(n))==1}
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Dec 25 2017
STATUS
approved