A382930 a(n) is the smallest k such that A382506(k) + sigma(k) = A000396(n).

1, 4, 16, 180, 2520, 7207200

Offset

1,2

Comments

Numbers k for which A382506 "jumps", there appears to be a remarkable relationship to A002182, the highly composites, in line with jumps for A382483 being in that series. See also the graph for A382506.

Links

Table of n, a(n) for n=1..6.

Example

A382506(16) = 465, 465 + sigma(16) = 496, which is perfect.

Crossrefs

Cf. A002093, A002182, A382506.

Sequence in context: A033911 A130691 A308239 * A012916 A012921 A280468

Adjacent sequences: A382927 A382928 A382929 * A382931 A382932 A382933

Keyword

nonn,more

Author

Leo Hennig, Apr 09 2025

Extensions

New name and a(1) from Jinyuan Wang, Apr 10 2025

a(6) from David A. Corneth, Apr 10 2025

Status

approved