login
A318459
a(n) = gcd(n, tau(n), phi(n)), where tau = A000005 and phi = A000010.
4
1, 1, 1, 1, 1, 2, 1, 4, 3, 2, 1, 2, 1, 2, 1, 1, 1, 6, 1, 2, 1, 2, 1, 8, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 1, 8, 1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 8, 1, 2, 1, 4, 1, 2, 3, 1, 1, 2, 1, 2, 1, 2, 1, 12, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 12, 1, 2, 1, 8, 1, 6, 1, 2, 1, 2, 1, 4, 1, 2, 3, 1, 1, 2, 1, 8, 1
OFFSET
1,6
LINKS
FORMULA
a(n) = gcd(n, A000005(n), A000010(n)).
a(n) = gcd(n,A009213(n)) = gcd(A000005(n),A009195(n)) = gcd(A000010(n),A009191(n)).
MATHEMATICA
Table[GCD[n, DivisorSigma[0, n], EulerPhi[n]], {n, 110}] (* Harvey P. Dale, Jul 30 2019 *)
PROG
(PARI) A318459(n) = gcd([n, numdiv(n), eulerphi(n)]);
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Sep 07 2018, after Labos Elemer's A074389
STATUS
approved