A074389 a(n) = gcd(n, sigma(n), phi(n)).

1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 4, 1, 2, 1, 1, 1, 3, 1, 2, 1, 2, 1, 4, 1, 2, 1, 4, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 6, 1, 4, 3, 2, 1, 4, 1, 1, 1, 2, 1, 6, 1, 8, 1, 2, 1, 4, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 1, 4, 1, 6, 1, 2, 1, 2, 1, 4, 1, 2, 1, 4, 1, 6, 1, 4, 1, 2, 1, 4, 1, 1, 3, 1, 1, 2, 1, 2, 3

Offset

1,6

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Formula

a(n) = gcd(n, A000010(n), A000203(n)).

a(n) = gcd(n, A009223(n)). - Antti Karttunen, Sep 07 2018

Mathematica

Table[Apply[GCD, {w, DivisorSigma[1, w], EulerPhi[w]}], {w, 1, 128}]

Prog

(PARI) A074389(n) = gcd([n, sigma(n), eulerphi(n)]); \\ Antti Karttunen, Sep 07 2018

Crossrefs

Cf. A000010, A000203, A073815, A050399, A009194, A009195, A009223, A074465, A074466.

In the old definition the erroneously given formula gcd(n, A000005(n), A000010(n)) is now sequence A318459. - Antti Karttunen, Sep 07 2018

Sequence in context: A376758 A304750 A104306 * A378887 A353688 A353666

Adjacent sequences: A074386 A074387 A074388 * A074390 A074391 A074392

Keyword

nonn

Author

Labos Elemer, Aug 23 2002

Extensions

Name corrected by Antti Karttunen, Sep 07 2018

Status

approved