A351459 Intersection of A349745 and A351458: numbers k for which k * gcd(sigma(k), A003961(k)) is equal to sigma(k) * gcd(k, A003961(k)) and also k * gcd(sigma(k), A276086(k)) is equal to sigma(k) * gcd(k, A276086(k)).

1, 345080736, 459818240, 51001180160

Offset: 1

Author

Antti Karttunen, Feb 18 2022

Keywords

• nonn
• more

Comments

All 3-perfect numbers (A005820) that are even and not multiples of 3 are included in this sequence, including also any hypothetical term of the form 4u+2.

If A323653 is indeed a subsequence of this sequence, then there are no odd perfect numbers. - Antti Karttunen, Jul 17 2023

Links

• Index entries for sequences computed from indices in prime factorization
• Index entries for sequences related to primorial base
• Index entries for sequences related to sigma(n)

Crossrefs

Intersection of A349745 and A351458.

Cf. A323653 (conjectured subsequence, all 23 known terms are present).

Cf. A000203, A003961, A005820, A276086.