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A297086 a(n) = 1 if gcd(n, phi(n)) == 1 otherwise 0. 4
1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET
1
COMMENTS
Characteristic function of A003277. - Iain Fox, Dec 25 2017
LINKS
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
Sequence in context: A080339 A294905 A353787 * A349920 A369253 A167752
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Dec 25 2017
STATUS
approved

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Last modified July 24 12:13 EDT 2024. Contains 374583 sequences. (Running on oeis4.)