A325636 - OEIS

A325636

a(n) = gcd(2n, sigma(n)).

1, 1, 2, 1, 2, 12, 2, 1, 1, 2, 2, 4, 2, 4, 6, 1, 2, 3, 2, 2, 2, 4, 2, 12, 1, 2, 2, 56, 2, 12, 2, 1, 6, 2, 2, 1, 2, 4, 2, 10, 2, 12, 2, 4, 6, 4, 2, 4, 1, 1, 6, 2, 2, 12, 2, 8, 2, 2, 2, 24, 2, 4, 2, 1, 2, 12, 2, 2, 6, 4, 2, 3, 2, 2, 2, 4, 2, 12, 2, 2, 1, 2, 2, 56, 2, 4, 6, 4, 2, 18, 14, 8, 2, 4, 10, 12, 2, 1, 6, 1, 2, 12, 2, 2, 6

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OFFSET

1,3

LINKS

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

Index entries for sequences related to sigma(n)

FORMULA

a(n) = gcd(2n, A000203(n)).

a(n) = gcd(2n, A033879(n)) = gcd(sigma(n), A033879(n)).

PROG

(PARI) A325636(n) = gcd(n+n, sigma(n));

CROSSREFS