A074465 -id:A074465 - cp's OEIS frontend

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

Labos Elemer, Aug 23 2002

nonn

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

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

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

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

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

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

Name corrected by Antti Karttunen, Sep 07 2018

A074466 a(n) = gcd(n^3, sigma(n^3), phi(n^3)).

Original entry on oeis.org

1, 1, 1, 1, 1, 24, 1, 1, 1, 20, 1, 8, 1, 8, 15, 1, 1, 3, 1, 4, 1, 8, 1, 24, 1, 4, 1, 16, 1, 1800, 1, 1, 3, 4, 25, 1, 1, 8, 1, 4, 1, 24, 1, 8, 3, 8, 1, 8, 1, 5, 9, 4, 1, 12, 1, 16, 1, 4, 1, 480, 1, 8, 1, 1, 65, 72, 1, 4, 3, 200, 1, 3, 1, 4, 5, 8, 1, 24, 1, 4, 1, 4, 1, 64, 5, 8, 3, 88, 1, 180, 7, 16, 1

Offset: 1

Labos Elemer, Aug 23 2002

nonn

			n=10: gcd[1000,2340,400] = 20 = a(10).

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

Cf. A053191, A074389, A074465, A175926.

[Gcd(n^3, Gcd(SumOfDivisors(n^3), EulerPhi(n^3))): n in [1..100]]; // Vincenzo Librandi, Sep 20 2018

Table[Apply[GCD, {w^3, DivisorSigma[1, w^3], EulerPhi[w^3]}], {w, 1, 128}]
GCD[#,DivisorSigma[1,#],EulerPhi[#]]&/@(Range[100]^3) (* Harvey P. Dale, Nov 03 2024 *)

A074466(n) = gcd([n^3, sigma(n^3), eulerphi(n^3)]); \\ Antti Karttunen, Sep 07 2018

a(n) = A074389(n^3).

cp's OEIS Frontend

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

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