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

1,2

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

Table of n, a(n) for n=1..4.

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.

Sequence in context: A113739 A159448 A316745 * A358705 A015381 A257384

Adjacent sequences: A351456 A351457 A351458 * A351460 A351461 A351462

Keyword

nonn,more

Author

Antti Karttunen, Feb 18 2022

Status

approved