A295313 - OEIS

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A295313

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

1, 1, 2, 1, 2, 4, 4, 1, 1, 6, 4, 4, 2, 8, 8, 1, 6, 3, 4, 6, 16, 12, 8, 4, 1, 6, 8, 8, 2, 24, 16, 9, 16, 18, 16, 1, 2, 4, 8, 6, 6, 32, 4, 12, 6, 24, 16, 4, 3, 3, 24, 14, 18, 8, 24, 8, 16, 6, 4, 24, 2, 32, 8, 1, 12, 48, 4, 18, 32, 48, 24, 3, 2, 6, 4, 4, 32, 24, 16, 6, 11, 18, 12, 32, 36, 4, 8, 12, 6, 18, 16, 24, 64, 48, 8

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OFFSET

1,3

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384

FORMULA

a(n) = A009195(A000203(n)).

PROG

(PARI) a(n) = my(sn = sigma(n)); gcd(sn, eulerphi(sn)); \\ Michel Marcus, Nov 23 2017

CROSSREFS

Cf. A000010, A000203, A009195, A295311, A295314, A295315.

Sequence in context: A323460 A129144 A360594 * A105022 A263293 A230535

Adjacent sequences: A295310 A295311 A295312 * A295314 A295315 A295316

KEYWORD

nonn

AUTHOR

Antti Karttunen, Nov 22 2017

STATUS

approved