OFFSET
1,1
COMMENTS
Numbers m such that A306695(m) = m are terms.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
6 is a term because gcd(6,2) <> gcd(6,12).
12 is a term because gcd(12,4) <> gcd(12, 24).
13 is not a term because gcd(13,12) = gcd(13, 14).
14 is not a term because gcd(14,6) = gcd(14, 24).
MAPLE
psi:= k -> mul((t+1)/t, t=numtheory:-factorset(k))*k:
select(t -> igcd(t, psi(t)) <> igcd(t, numtheory:-phi(t)), [$1..1000]); # Robert Israel, Apr 28 2019
PROG
(PARI) dpsi(n) = n * sumdivmult(n, d, issquarefree(d)/d); \\ A001615
isok(k) = gcd(k, eulerphi(k)) != gcd(k, dpsi(k)); \\ Michel Marcus, Mar 21 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Torlach Rush, Mar 05 2019
STATUS
approved