A297170 - OEIS

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A297170

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

1

1, 1, 1, 1, 1, 2, 1, 1, 2, 4, 1, 4, 1, 2, 1, 1, 1, 3, 1, 2, 1, 2, 1, 4, 2, 4, 1, 4, 1, 2, 1, 1, 5, 4, 1, 1, 1, 2, 1, 2, 1, 6, 1, 20, 3, 2, 1, 4, 2, 1, 1, 2, 1, 6, 1, 8, 1, 4, 1, 4, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 4, 1, 4, 1, 6, 1, 2, 2, 4, 1, 4, 1, 2, 1, 4, 1, 24, 3, 4, 5, 2, 1, 4, 1, 1, 3, 1, 1, 2, 1, 2, 3

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OFFSET

1,6

LINKS

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

FORMULA

a(n) = gcd(A000010(n), A001065(n)).

PROG

(PARI) A297170(n) = gcd(eulerphi(n), sigma(n)-n);

CROSSREFS

Cf. A000010, A000203, A001065, A009223.

Sequence in context: A029265 A103648 A293176 * A359627 A127309 A097853

Adjacent sequences: A297167 A297168 A297169 * A297171 A297172 A297173

KEYWORD

nonn

AUTHOR

Antti Karttunen, Mar 03 2018

STATUS

approved